I think a commitment is a commitment and your word should be mean something - especially if it is formalized and faxed in.
However, the kids are the ones who are at a real disadvantage here....
There are only a maximum of 25 spots available (generally speaking - no back-counting). If a kid waits b/c of rumors, he could be left waiting at the station and the train is already gone. Hello FBS. If he does sign b/c of a great relationship with a coach and the coach leaves, then he's got 4-5 years to get NFL ready with new coaches who almost always prefer "their recruits" to the other guy's. Proverbial rock and hard place.