I have not had that problem, but I believe it is two fold. One, I believe the main issue is poor fitting rental gear. (good reason to get your own stuff) The other is the over inflation thing. If we remember the neutral bouyancy training we find small amounts of air adjustment are smarter and will keep you on the surface. If you dump a great deal of air into an ill fitted BCD it seems like you would be over inflating to get a snug feeling. This could lead to a possible Third scenario.... BCD failure if it is older and not well maintained. I have used both types of BCD and have not had the problem you spoke of. Glad you got out of it in one piece. Your story is another example of why you should always dive with your buddy. Take care.
Brent