Plaintiffs-appellants, Mr. and Mrs. Tommerup, filed suit against defendant-respondent, Albertson’s Inc., for personal injuries sustained by Mrs. Tommerup in a slip and fall accident in the parking lot of an Albert-son’s grocery store in Twin Falls, Idaho. The case was tried before a jury in February of 1977 after the district court had denied motions of both parties for summary judgment. The jury returned a verdict in favor of defendant, finding that defendant was not negligent in the action. Judgment was entered in accordance with the verdict and plaintiffs have appealed that judgment.
The record at trial disclosed the following facts. On Sunday, September 17, 1972, Mrs. Tommerup upon exiting an Albertson’s grocery store in Twin Falls slipped and fell on a cupcake wrapper which apparently had been discarded in the parking lot near the doorway of the grocery store. The parking lot and grocery store were controlled solely by the defendant-respondent. This slip occurred as Mrs. Tommerup was leaving the premises after purchasing groceries in the store. Mrs. Tommerup suffered injury to her right foot in the fall. The incident was immediately reported to the assistant store manager.
There was no direct evidence as to who deposited the cupcake wrapper near the door. The evidence did show that Albert-son’s sold its own bakery goods in the store and also commercially-packaged bakery goods. Albertson’s did not maintain trash containers near the doorway of its store. Plaintiffs introduced exhibits which showed that at the time the action came to trial, similar stores in the area maintained such trash containers near the doorways of their stores. Although store personnel were instructed to pick up paper and debris outside the store as they saw it, the only regularly scheduled inspection and cleanup of the concrete apron and parking lot in front of the store took place between midnight and 6:00 o'clock a. m. On the above evidence, the jury returned a verdict in favor of the defendant.
The following facts were not disclosed to the jury at trial but were presented by the plaintiffs in their motion for summary judgment and as an offer of proof at trial. On September 21, 1972, four days after the accident, an agent for Albertson’s wrote to Mrs. Tommerup asking her to submit bills incurred as a result of the accident. Mrs. Tommerup replied to the letter and questioned how she should evaluate items of damage which did not represent out-of-pocket medical expenses. The agent for Albertson’s replied it was willing to accept all bills in reference to the accident, and that, when Mrs. Tommerup was “in a posi*3tion to finalize the claim,” it would “work directly with [her].” Mrs. Tommerup stated that on receipt of the letter she believed that Albertson’s had admitted liability for all purposes and had agreed to settle the general damages when those damages could be ascertained. The Tommerups at this time did not consult an attorney as to their rights with respect to the accident.
From September, 1972, through January, 1975, Albertson’s paid out some $3,800 in medical expenses for the injuries of Mrs. Tommerup. An additional $673 was paid through the month of November, 1975. At that time Albertson’s advised the Tommerups that no further payments would be made on their claim. The Tommerups then sought legal advice and now argue that they were lulled into a situation in which they were unable to reconstruct adequately the details of the accident.
The above facts were presented to the court by plaintiffs’ motion for summary judgment on September 22,1976, which motion was denied. Plaintiffs again presented the same set of facts in an offer of proof at trial for the purpose of showing an admission of liability or estoppel to deny liability on the part of defendant-respondent Albertson’s.
I
The Tommerups first assign as error the instructions given by the trial court on the issue of liability of an owner or possessor of land for injuries caused by a dangerous condition on the premises. The jury was instructed that mere proof of the existence of a defective condition does not, in itself, establish negligence; among other things, it must additionally be shown that the owner or possessor had actual or constructive knowledge of the defect and failed to remove or correct it as soon as would have been done in the exercise of ordinary care.
The first issue presented on appeal is whether, before an owner or possessor of land is liable for injury to an invitee caused by a defective condition on his land, it must be shown that the owner or possessor had actual or constructive knowledge of the defective condition.
We answer the question in the affirmative. The law is well settled in this state that, to hold an owner or possessor of land liable for injuries to an invitee caused by a dangerous condition existing on the land, it must be shown that the owner or occupier knew, or by the exercise of reasonable care should have known, of the existence of the dangerous condition. Mann v. Safeway Stores, Inc., 95 Idaho 732, 518 P.2d 1194 (1974); Giles v. Montgomery Ward Co., 94 Idaho 484, 491 P.2d 1256 (1971); Otts v. Brough, 90 Idaho 124, 409 P.2d 95 (1965); Martin v. Brown, 56 Idaho 379, 54 P.2d 1157 (1936).
Appellants urge this Court to adopt a much stricter standard in the determination of a landowner’s (or possessor’s) duty to his invitees. In their view, the requirement of proving the owner’s or possessor’s knowledge (either actual or constructive) imposes an unjust hardship on the plaintiff in a slip and fall case such as this. They contend the plaintiff is in a very difficult position to carry the burden of proof on the issue because he usually has no prior knowledge of the condition, is surprised and upset by the accident, and therefore unable to gather evidence to prove how long the condition existed, does not know of the proof requirement at the time when evidence could best be gathered, and most of the people who are best able to supply the evidence are employees of the proprietor with an interest adverse to the plaintiff.
Although these contentions may at times be correct, they fail to address the real issue. The knowledge requirement did not arise out of consideration of the parties’ respective difficulties in proving the facts at trial. The correct analysis has been stated before:
“The owner is not an insurer of such [invitees] . . . . Nor is there any presumption of negligence on the part of an owner or occupier merely upon the showing that an injury has been sustained by one while rightfully upon the premises. The true ground of liability is *4the propriétor’s superior knowledge of the perilous instrumentality and the danger therefrom to persons going upon the property. [Mautino v. Sutter Hospital Association, 211 Cal. 556, 296 P. 76 (1931)].” Martin v. Brown, 56 Idaho at 382, 54 P.2d at 1158. (emphasis ours)
Because the true ground of liability is the superior knowledge of the owner or possessor, we fail to see any justification for holding him liable for injury caused by defects about which he had no knowledge, when the lack of knowledge was not due to a failure by the owner or possessor to use ordinary care.
Appellants argue, however, that the nature of respondent’s business was such that it created a reasonable probability that the dangerous condition would arise in the normal course of business, and that respondent’s actual or constructive knowledge of the specific defect need not have been proved.
Appellants cite Jasko v. F. W. Woolworth Co., 177 Colo. 418, 494 P.2d 839 (1972) in support of their argument. That case, however, is readily distinguished on its facts. In Jasko, the plaintiff was injured in the defendant’s store when she slipped on a slice of pizza which was on the terrazzo floor. An associate manager of the store testified that 500-1,000 individuals per day purchased one or more slices of pizza at the pizza counter. There were no chairs or tables by the counter. Many customers stood in the aisle and ate the pizza from the waxed paper sheets upon which they were served. When pizza was being consumed, porters “constantly” swept up debris from the floor.
In reversing an order granting defendant’s motion for summary judgment, the Colorado Supreme Court held defendant’s method of selling pizza was one which led inescapably to such mishaps as that of the plaintiff, and in such a situation conventional notice requirements (i. e. actual or constructive knowledge of the specific condition) need not be met. The court there stated:
“The practice of extensive selling of slices of pizza on waxed paper to customers [to] consume it while standing creates the reasonable probability that food would drop to the floor. Food on a terrazzo floor will create a dangerous condition. In such a situation, notice to the proprietor of the specific item on the floor need not be shown. . . . ”
The court further stated:
“ ‘The mere presence of a slick or slippery spot on a floor does not in and of itself establish negligence, for this condition may arise temporarily in any place of business. [Cite] Nor does proof of a slippery floor, without more, give rise to an inference that the proprietor had knowledge of the condition. [Cite] But we are not dealing with an isolated incident’ ” Jasko v. F. W. Woolworth Co., supra, 494 P.2d at 840.
The record in the instant case is devoid of evidence indicating the condition which caused appellant’s injury to have been other than an isolated incident.
Under appellants’ proposal, liability could be imposed upon a defendant storeowner if a customer, shopping in its store, discarded a piece of litter in an aisle upon which a second customer slipped and fell five seconds later. This despite no opportunity, reasonable or otherwise, for the defendant to prevent such an occurrence. We decline appellants’ invitation to foster such an unreasonable result. The instruction given by the trial court on the issue of respondent’s knowledge of the dangerous condition was correct.
II
Appellants next argue the trial court erred in instructing the jury that there is no duty on the part of the owner to warn the invitee of obvious and ordinary risks attendant on the use of the premises, and that the owner is under no duty to reconstruct or alter the premises so as to obviate such known or obvious dangers. We find no error. The duty to keep the premises safe for an invitee only requires the exercise of ordinary care, and does not *5extend to dangerous conditions which are known to the invitee, or which are or by the exercise of ordinary care should have been observed by the invitee. Otts v. Brough, supra. In the usual case, there is no obligation to protect the invitee against dangers which are known to him, or which are so obvious and apparent to him that he may reasonably be expected to discover them. Against such conditions it may normally be expected that the visitor will protect himself. Prosser, Handbook of the Law of Torts, § 61, p. 394.
Ill
Appellants next assign as error the trial court’s denial of their motion for partial summary judgment. Appellants moved for summary judgment on the issue of liability
“on either or both of the following grounds:
1. That the defendant Albertsons, Inc., has admitted liability to the plaintiffs.
2. That the conduct of the defendant in assuming the obligation to pay medical expenses and other damages for more than three years after the accident before denying liability has so seriously prejudiced the plaintiffs in gathering and retaining evidence to support . . . liability that . defendant is estopped from denying liability. .
. To the extent it may be necessary for plaintiffs to amend their pleadings to conform to the evidence of estoppel plaintiffs so move.”
On appeal, appellants argue that under promissory estoppel, equitable estoppel, or quasi estoppel, their motion for summary judgment on the issue of liability should have been granted.
Promissory estoppel, as opposed to equitable estoppel or quasi estoppel, is inapplicable in this appeal. The complaint set forth claims in tort only and promissory estoppel is a contract doctrine pertaining to the enforceability of contracts otherwise lacking consideration. Appellants’ motion to amend their pleadings “to conform to the evidence of estoppel” must be read in conjunction with the second stated ground for their motion for summary judgment, which addressed the conduct, as opposed to any promise, of respondent. The issue of promissory estoppel was not raised below and will not be considered now. Heckman Ranches, Inc. v. State, By and Through Dept. of Public Lands, 99 Idaho 793, 589 P.2d 540 (1979).
With respect to appellants’ claim that their motion for summary judgment should have been granted on the theories of equitable estoppel or quasi estoppel, it is clear that the trial court’s denial thereof was correct. As we stated in City of Nampa v. Swayne, 97 Idaho 530, 547 P.2d 1135 (1976), the application of equitable estoppel is dependent upon a case by case analysis of the equities involved. 97 Idaho at 534, 547 P.2d at 1139. The equities in the instant case support the trial court’s ruling. The conduct by respondent which appellants argue should support an estoppel on the issue of liability consisted of (1) a letter which read, in pertinent part,
“[W]e are willing to accept all of the bills in reference to this accident. When you are in a position to finalize the claim, we most certainly will work directly with you as we prefer working with our customers by mail if at all possible.”
and (2) payment by respondent of appellants’ medical bills and certain household bills for a period of about three years.
In the case of Bjornstad v. Perry, 92 Idaho 402, 443 P.2d 999 (1968), this Court stated:
“Equitable estoppel generally requires that a false representation or concealment of a material fact be made with actual or constructive knowledge of the true state of facts; that the party to whom the false representation was made was without knowledge or the means of acquiring knowledge of the real facts; that the false representation was made with the intent that it be acted upon; and that the party to whom it was made relied and acted upon it to his prejudice.” 92 Idaho at 405, 443 P.2d at 1002.
*6All of the above factors are of equal importance and there can be no estoppel absent any of the elements. Idaho Title Company v. American Insurance Company, 96 Idaho 465, 531 P.2d 227 (1975); Alder v. Mountain States Tel. & Tel. Co., 92 Idaho 506, 446 P.2d 628 (1968). It is difficult to see how respondent could be said to have made a false representation or concealment of any material fact in the instant case. The only statements made by the respondent relevant to this case were that it was “willing to accept all of the bills in reference to [the] accident,” and that, when appellants were in a position to “finalize the claim,” it would “work directly” with them. There is nothing in the record to indicate that at the time the statement was made, respondent was not willing to accept the bills or to work directly with the appellants'in settling the claim. It was only after respondent had paid appellants some $3,800 over a three-year period that it became un willing to accept further bills, and at that time appellants were so informed.
Appellants further contend, however, that no misrepresentation or reliance need be shown, as the case falls within the parameters of “quasi estoppel.” We disagree. To constitute quasi estoppel, the person against whom the estoppel is sought must have gained some advantage for himself, produced some disadvantage to the person seeking the estoppel, or induced such party to change his position; in addition it must be unconscionable to allow the person against whom the estoppel is sought to maintain a position which is inconsistent with the one in which he accepted a benefit. Dawson v. Mead, 98 Idaho 1, 557 P.2d 595 (1976); KTVB, Inc. v. Boise City, 94 Idaho 279, 486 P.2d 992 (1971).
The first element of quasi estoppel is the initial taking of a position by the party against whom the doctrine is to be applied. Respondent stated its willingness to accept appellants’ bills, and actually paid such bills for a three year period. Whether this conduct amounted to a “taking of a position” by respondent that it was admitting liability, so as to support appellants’ argument for application of quasi estoppel, is doubtful. While respondent’s statement that it would “work directly with” appellants when they were “in a position to finalize the claim” arguably supports appellants’ contention, it is equally reasonable to construe the statement as indicating only that respondent’s “position” was that it was willing to seek some mutually acceptable arrangement whereby appellants’ financial burden arising from the incident could be alleviated.1
However, we need not decide which construction is compelled in this case, because even if we were to assume, arguendo, that a position of admitting liability was taken by respondent, there is no indication that respondent obtained any benefit, or caused appellants any injury, such that it would be unconscionable to allow respondent to assert its position of non-liability at trial. In KTVB v. Boise City, 94 Idaho 279, 486 P.2d 992 (1971), this Court discussed the doctrine of quasi estoppel at some length. There the Court reaffirmed its approval of the following:
“ ‘The doctrine classified as quasi estoppel has its basis in election, ratification, affirmance, acquiescence, or acceptance of benefits; and the principle precludes a party from asserting to another’s disadvantage, a right inconsistent with a position previously taken by him. The doctrine applies where it would be unconscionable to allow a person to maintain a position inconsistent with one in which he acquiesced or of which he accepted a benefit.’ ” [Quoting from Clontz v. Fortner, 88 Idaho 355, 364-365, 399 P.2d 949, 954 (1965)]. (emphasis ours) 94 Idaho at 281, 486 P.2d at 994.
*7The Court went on to quote with approval the following from Godoy v. Hawaii, 44 Haw. 312, 354 P.2d 78 (1960):
“ ‘This class of estoppel is based upon the broad equitable principle which courts recognize, that a person, with full knowledge of the facts, shall not be permitted to act in a manner inconsistent with his former position or conduct to the injury of another. To constitute this sort of estoppel the act of the party against whom the estoppel is sought must have gained some advantage to himself or produced some disadvantage to another; or the person invoking the estoppel must have been induced to change his position . . . ” (emphasis ours) 94 Idaho at 281, 486 P.2d at 994.
In the instant case, there has been no showing of any unconscionable retention of benefit by respondent. Although the statute of limitations had run on appellants’ claim before this action was filed, respondent did not assert the statute as a defense. Appellants were given the opportunity to litigate fully the issue of liability, despite the running of the statute, and the jury found against them. It would be anomalous to hold that respondent, by paying appellants over $3,800, gained any advantage, or placed appellants at any disadvantage, when it has been determined at a full trial on the liability issue that respondent was under no obligation to pay appellants anything.
Appellants argue, however, that the statement made by respondent and its payment of the bills over the three-year period led them to believe liability would not be contested, and that as a result they lost the opportunity to gather evidence effectively and to reconstruct the details of the accident. They claim this possible loss of opportunity constitutes a disadvantage to them which supports application of quasi estoppel against the respondent. We disagree. To adopt the position of appellants would require that we first assume there was in fact more evidence to be gathered at some earlier time. That assumption made, we are then asked to go still further and assume also that such evidence would have been favorable to appellants and adverse to respondent. We decline to engage in this compound conjecture; application of quasi estoppel cannot be based on so infirm a foundation.
For the foregoing reasons, we find no error in the trial court’s denial of appellants’ motion for summary judgment. To hold otherwise would virtually eliminate the commendable practice of parties attempting to reach equitable solutions on their own. It has always been the policy of the law to favor compromise and settlement; and it is especially important to sustain that principle in this age of voluminous litigation. Mustang Equipment, Inc. v. Welch, 115 Ariz. 206, 564 P.2d 895 (1977); Dansby v. Buck, 92 Ariz. 1, 373 P.2d 1 (1962); Kroetch v. Empire Mill Co., 9 Idaho 277, 74 P. 868 (1903). We decline to hold that financial assistance to an injured party places a lock on liability.
IV
In a related issue, appellants challenge the ground upon which the trial court refused to allow in evidence testimony that respondent paid Mrs. Tommerup’s medical bills and certain household expenses for the three-year period after the accident. The trial court refused to allow this evidence before the jury on the ground that I.C. § 41 — 1840 absolutely barred consideration of such evidence. The statute provides:
“(1) No payment or payments made by any person, or by his insurer by virtue of an insurance policy, on account of bodily injury or death or damage to or loss of property of another, shall constitute an admission of liability or waiver of defense as to such injury, death, loss or damage, or be admissible in evidence in any action brought against the insured person or his insurer for damages, indemnity or benefits arising out of such injury, death, loss or damage unless pleaded as a defense to the action.
(2) All such payments shall be credited upon any settlement with respect to the same damage, expense or loss made by, or judgment or award rendered therefor in *8such an action against, the payor or his insurer, and in favor of any person to whom or on whose account payment was made.” I.C. § 41-1840.
Appellants argue that the statute is applicable only to payments made to another by an insured and that, whereas respondent is self-insured for liability up to $100,000, the statute is inapplicable to this case (notwithstanding the fact that respondent is insured by an independent company for any liability over and above that amount). We find the contention without merit. Although the language of the statute refers at times to “any person” and at times to “the insured,” we are of the opinion that the purpose of the provision is to encourage any defendant, insured or otherwise, to assist an injured adversary in alleviating any losses suffered without the fear of providing an admission which could result in the imposition of liability. Accordingly, we hold the statute applicable whether the person making such payments be insured or not. We note in passing that even if the statute were held applicable only to payments made by an insured, whereas the amount sought by appellants in this case exceeded the amount up to which respondent was self-insured by some $400,-000, respondent did in fact have the status of an “insured.” The trial court’s application of I.C. § 41-1840 to the case at bar, precluding admission into evidence of the payments made by respondent, was correct.2
V
Respondent in this action has also urged on appeal that the trial court erred in giving a particular instruction and in admitting certain exhibits in evidence. Since respondent was the prevailing party at trial and has filed no cross-appeal in this cause, it is not necessary to decide these issues and we express no opinion as to their validity.
Affirmed.
SHEPARD, J., and DUNLAP, J. Pro Tern., concur.. We note that one of the two stated grounds in appellants’ motion for partial summary judgment was “[t]hat defendant Albertson’s, Inc., has admitted liability to the plaintiffs.” However, there is nothing in appellants’ brief addressing the question whether respondent’s statements, in and of themselves, constituted legally binding admissions of liability. We therefore express no opinion on that issue.
. Appellants have not raised the question whether I.C. § 41-1840 precludes admission into evidence of payments only but not promises to pay, and we therefore draw no distinction here.