I would think so, but without a 1-800-PHONE-THX type hotline around, who's going to fink on them?
I've had theaters shut the credits off on the final show of the night. Bad showmanship.
I think Star Wars was the movie that first made me want to stick around for the closing credits. And in the years that followed, I would start to recognize the names of all the ILM guys on other films.