I've heard of this happening. People can change their minds for various reasons but make sure the advice you heard about the facilities/price is fairly accurate. It's of course hard to be sure without going to the school yourself and seeing, but talk to students at UPenn and find out about their experience and if it's been positive/negative/worth the cost, etc. You could always wait on submitting the supplemental assuming there's no near deadline for it and give it some thought/time 🙂 If you do decide against it for sure, then that's okay too. Others have done that in the past so don't worry about it! There's no reason to pay extra for a school you know you're not interested in at all.