People show up for CRT, Akershus, California Grill, et al, because they're "event meals". The no-show rate for those would be far lower than for a more typical restaurant even with no credit card guarantee.
If folks get dinged ten bucks for not showing up to lunch at Morocco in the middle of January when the place is 85% empty, of course there are going to be complaints. And Disney very much tries to minimize complaints. They're bad for business.