I could pick any random name with a whitelist, and say that it's me. If the provider asked me to send them a pm to verify that it was me, I could just say I don't have VIP so I can't. The problem is that there's no real way to connect a TER account with the person attempting to make an appointment. TER does not require any form of ID to get a membership, or make any attempt to screen members.

Then there's the chance that someone (ie psycho, rapist, etc) could hack an account, or LE could easily make an account and then coerce a provider into giving it a whitelist. Or even attempt to make a provider account and give himself a whitelist. TER simply has no safeguards in place to stop this sort of thing.

So while a whitelist is certainly nice, I wouldn't accept it as my sole form of verification. From my point of view it's really very simple. If it doesn't require the release of verifiable personal information to confirm your identity, then it's simply not acceptable for screening.