I don't see them doing anything out of the ordinary...people who bought tickets for Monday should get to use those if there is a game.
Well that right there would be out of the ordinary. It's a long-held tradition that if a fan has opening day tickets, those tickets are good for the first game. Thus if the Opener is delayed and then played on a date when there is another game scheduled, the scheduled game is postponed. This happens rarely because most of the time no game is scheduled for the day after the Opener, so if it's played that day, no problem. But it has happened.
And if you want to say, but the fans holding tickets for the scheduled game are going to be really pissed .... yeah, they're going to be really pissed.