concurring.
I agree for the most part with the majority opinion. However, I write separately because I disagree in two minor respects with the majority opinion’s discussion of the mootness issue.
First, although I agree with the majority that this case should not be dismissed for mootness, I have a slightly different basis for that conclusion. There is a recognized exception to the mootness principle which allows a court to decide a case which might in a technical sense be moot but which presents an important question capable of repetition but evading review. Jersey Shore Area School District v. Jersey Shore Education Association, 519 Pa. 398, 548 A.2d 1202 (1988); Minersville Area School District v. Pennsylvania Labor Relations Board, 130 Pa.Commonwealth Ct. 475, 568 A.2d 979 (1989); Cytemp Specialty Steel Division, Cyclops Corp. v. Public Utility Commission, 128 Pa.Commonwealth Ct. 349, 563 A.2d 593 (1989); In re General Election, November 8, 1988, 126 Pa.Commonwealth Ct. 450, 560 A.2d 260 (1989). I believe this is such a case.1
*502I also do not agree with the majority’s suggestion that a court would not dismiss a case as moot if a party fails to preserve an objection based upon mootness. See majority opinion at 497, n. 2. Unless a case falls within an exception to the mootness doctrine, a court is obliged not to decide a case which is moot. See In re Gross, 476 Pa. 203, 382 A.2d 116 (1978); Cytemp Specialty Steel Division; Pennsylvania Liquor Control Board v. Dentici, 117 Pa.Commonwealth Ct. 70, 542 A.2d 229 (1988); Benojfv. Zoning Board of Adjustment, 107 Pa.Commonwealth Ct. 578, 528 A.2d 705 (1987). This sound policy against rendering advisory opinions requires that a court act sua sponte to dismiss a moot case, and no procedural default by a party possibly could justify a court deciding a moot case in the absence of an exception to the mootness doctrine. Therefore, DPW’s argument that the Defender Association did not properly raise the mootness question in the trial court is irrelevant.
. The majority concludes that this case should not be dismissed as moot because "the mootness depends on no permanent change in the *502facts or the law but only on the possible changeable desires of a committed person regarding discharge____" Majority opinion at 497. I cannot subscribe to this expression of what apparently is a new exception to the mootness doctrine recognized by the majority. A case always may be rendered moot by the “changeable desires" of a party who decides to give up the dispute. The fact that the party here is the subject of a mental health commitment does not of itself require a different analysis regarding mootness.