when I check in next month and have to wait in line because someone is arguing with a CM that little Cindy Lou Who booked this room and is only 4
Why would there be an argument? If you email Disney, they'll call you back. Ask your question and if it's possible, they'll tell you sure..child's AP's can be used for rooms...just make the ressie in the adults name. Little Cindy Lou can't have a ressie if she's 4. If you ask the caller, she'll email you the reply. If you have a problem (and I can't see why you would), just show them the email, which comes with a phone number and case number on it.
In any case, just ask Disney, instead of people on this list, who don't get to make the decision (and don't misunderstand me..this list is wonderful for answers..but clearly some don't agree on this). While this list is good for answers based on experience, Disney, the resort owner is the only one who can tell you if a certain policy is in place and enforced.
editted to add..where did you call? Curious, because I find that reservations, believe it or not, is seldom a good place for official Disney answers. I prefer customer service, and when I email, I always get a phone call in response. They will back it up with an email. Obviously, if policy has changed, then you would have to get an adult AP..but as of September, child's AP was fine (jfi, I have an adults AP..I didn't need to use a child's AP..I asked for another person).