concurring in the judgment:
I agree that the district court should be reversed but on the narrow ground that the Hotel failed to object before the arbitrator to restoration of the eliminated bus positions— the issue on which Local 25 sought clarification. See 12/14/94 Letter from Union Requesting Clarification from Arbitrator (JA 87-89).1 By not objecting to submission of *860the restoration issue to the arbitrator, the Hotel waived its right to challenge in court the scope of the submission and the arbitrator’s authority thereunder to resolve the issue.2 Cf. Davis v. Chevy Chase Fin. Ltd., 667 F.2d 160, 165 (D.C.Cir.1981) (finding no waiver because party “did ... raise the arbitrability question” before arbitrator “with full reservation of his right to have the arbitrator’s determination subjected to judicial review’’); see also United, Industrial Workers v. Government of the Virgin Islands, 987 F.2d 162, 168 (3d Cir.1993) (“[Because arbitrators derive their authority from the contractual agreement of the parties, a party may waive its right to challenge an arbitrator’s authority to decide a matter by voluntarily participating in an arbitration and failing to object on the grounds that there was no agreement to arbitrate.”); Jones Dairy Farm v. Local No. P-1236, United Food & Commercial Workers Int’l Union, 760 F.2d 173, 175 (7th Cir.), cert. denied, 474 U.S. 845, 106 S.Ct. 136, 88 L.Ed.2d 112 (1985); George Day Constr. Co. v. United Bhd. of Carpenters & Joiners of Am., Local 35b, 722 F.2d 1471, 1475-76 (9th Cir.1984); Piggly Wiggly Operators’ Warehouse, Inc. v. Piggly Wiggly Operators’ Warehouse Indep. Truck Drivers Union, Local No. 1, 611 F.2d 580, 584 (5th Cir.1980). Once the bus positions were restored, they became, as the arbitrator observed unexceptionably, “subject to being filled as vacancies in accordance with the [Collective Bargaining] Agreement.” 6/6/96 Clarification Letter at 3 (JA 43) (quoting 2/6/95 Clarification Letter at 3 (JA 40)). The arbitrator was therefore justified in directing the Hotel to “fill” and “operate with” the restored busing positions “until it can demonstrate an appropriate basis under the Agreement, to abolish such positions.” Id. at 9.(JA 49). Given the Hotel’s waiver, there is no need to explore here the metes and bounds of arbitral authority, as the majority has done. Since the majority has chosen to do so, however, I will respond briefly.
First, it should be noted that our circuit is not always eager to enforce arbitration agreements so strictly. See Cole v. Burns Int’l Sec. Servs., 105 F.3d 1465, 1489 (D.C.Cir.1997) (holding arbitration ágreement binding on Title VII plaintiff only if employer agrees to pay arbitration costs). Second, I do not agree with the majority’s assertion that there is “nothing to cast the slightest doubt on the arbitrator’s judgment about the scope of this arbitration.” Majority Op. at 4. The arbitrator’s first decision, on the merits, treated the arbitration as having been brought on behalf of and to provide a remedy for the named grievants only—a view the arbitrator acknowledged in each of the clarification letters. See 2/6/95 Clarification Letter at 2 (JA 39) (“The Arbitrator notes that the remedy set forth in the [January 2, 1994] Opinion contemplated reinstatement of, and a make whole award to, the identified Grievants only. That is, nothing in this Arbitration proceeding raised, or was intended to resolve, any issue with respect to any potential remedy to any individuals other than the identified Grievants.”) (emphasis added); 6/6/96 Clarification Letter at 8 (JA 48) (“[I]t is correct that the Arbitrator, in finding the violation, balanced Management’s right to manage, including the right to determine staffing, against the Grievants’ seniority rights____”) (emphasis added). The ten- or of the merits decision presumably reflects the intent of the parties at that time, as expressed in their briefs and at the hearing. And the scope of an arbitrator’s authority is limited to those subjects the parties intend to submit to arbitration. See Williams v. E.F. Hutton & Co., 753 F.2d 117, 119 (D.C.Cir.1985) (“There is no duty to arbitrate matters not subject to the arbitration agreement, and no authority on the part of arbitrators to consider matters not .necessary to the resolution of disputes actually submitted.”) (citing Davis, 667 F.2d at 165) (emphasis added); Washington-Baltimore Newspaper Guild, Local 35 v. Washington Post Co., 442 F.2d 1234, 1236 (D.C.Cir.1971) (“In determining the scope of an arbitrator’s authority we look to two sources: the collective bargaining agreement, and the submission of the parties to the arbitrator.”) (emphasis added); Matteson v. Ryder Sys. Inc., 99 F.3d 108, 114 (3d Cir.1996) (“[T]he touchstone for interpreting a submission must be the intention of the parties.”). If an arbitrator oversteps the authority delegated by the parties, it is the duty of the reviewing court to rein him in. *861See Matteson v. Ryder Sys. Inc., 99 F.3d at 113-15 (reversing arbitral decision “[b]ecause the [arbitral tribunal] exceeded its authority as arbitrator by deciding issues not submitted to it by the [parties]”); John Morrell & Co. v. Local Union 304A of the United Food & Commercial Workers, 913 F.2d 544, 559-61 (8th Cir.1990) (affirming district court determination that arbitral decision was beyond scope of issues submitted because appellate court was “satisfied that the arbitrator was not ‘even arguably ... acting within the scope of his authority5 ”), cert. denied, 500 U.S. 905, 111 S.Ct. 1683, 114 L.Ed.2d 78 (1991); Bowater Carolina Co. v. Rock Hill Local Union No.1924, 871 F.2d 23 (4th Cir.1989) (directing district court to vacate decision on issue not submitted by parties); Courier-Citizen Co. v. Boston Electrotypers Union No. 11, 702 F.2d 273, 280-81 (1st Cir.1983) (vacating district court order enforcing back pay award to employee not mentioned in submission). Nonetheless, because the Hotel faded to object before the arbitrator to the expanded scope of the arbitration, it has waived any right to do so now.
. In opposing Local 25's clarification request, the Hotel’s counsel argued only that the arbitra-tor lacked authority to fill the restored, but vacant, positions. See Letter from Hotel Counsel to Arbitrator in Opposition to Union Clarification Letter at 1 (JA 90) (whether "the hotel must hire new buspersons to fill the classification" "is not before the arbitrator”).
. Waiver was not argued to the initial panel.