You shouldn't have any problems my ID is cracked down the center a good 3/4 of the way. I have yet to get any problems. Lady at IAH asked what happened and at MSP they took a magnifyer to it, at ORD the lady just commented how beat it was.

I would think aslong as the protective filming on them isn't peeling you will be fine, even if its cracked over some data. My ID also isn't scanable too as I had trouble in Iowa a year ago trying to get into a casino boat.
If they do say something I always tell them it expires at end of 2010 so I get a new one soon.