I havent heard that saying but I cant say I agree with it. Morris Brown is pretty much out the picture, its rare that anyone in the AUC recognizes them. The only stereotype i've heard from being in the AUC is that CAU girls keep it real while Spelmanites are stuck up. And there is SOME truth to that, depending on who you deal with.
I would disagree with that statement that some Spelman students are stuck up. That is just girls in general or people in general. Im sure EVERY campus has atleast one girl who other people think are stuck up.
Definitely go to Spelman...Im biased though. But cross registering doesnt allow you to get two different degrees from two different institutions, as stated above the degree would come from Spelman.