I played a guy that brought 4 different demo racquets to a tournament. The guy was sandbagging (self admitted) so he could take his team to 3.0 nationals. He then got a double bump to 4.0. He said he wasn't expecting to win and he was checking out new racquets because he needed a new one. Not sure why he entered a tournament though to test out demo racquets.
Funny thing is during changeovers he would tell me what he thought about each racquet and what he did or didn't like about them.