This is quite frustrating and confusing. I thought it was required to use the tool. I'm holding out for a school I'm WL at, but I thought I was required at a minimum per AAMC to PTE to one of my acceptances by today. The only guidance I received from the school I PTE'd is that I "should" release any additional acceptances beyond that one, and that if I intend to enroll there, I "should" choose PTE. It doesn't say "it's ok/not ok to not select anything if you're waiting to hear from somewhere else" or "if you don't PTE, you will/will not lose your seat." Out of anxiety that I may end up with zero seats at the end of it all, I PTE'd, but perhaps I didn't have to.