I think there is a happy medium between the two extreme. At any given hotel, certain codes produce substantial savings others do not. I suspect that codes belong to companies in which id is more likely to be the norm.

For example, asking to see a AAA card is pointless. Everyone has one and usually the savings isn't that great. I suspect relatively little abuse.

But if the hotel is near a major University or major corporation, that entity is more likely to have negotiated a substantial savings. As such, it is likely that their codes are more likely to be abused. Fortunately, those entities are also the most likely to issue identification, travel orders or have a travel office.

Therefore someone using that rate code should be more likely to be asked for identification that someone using a ubiquitious code like AAA.

Just my $0.02