If I'm selling something on eBay or Bonanzle, I put that I'm a TPF member. I encourage people to look me up/PM me, and also link them to the proper authentication thread so that they can ask questions (if they need to) about the item here. I understand that not everyone is truthful in who they are, but I'm a "glass-half-full" person, so I always give people the benefit of the doubt. If someone puts that they are a TPF member on an auction, it does make me feel better. I usually am knowledgeable about the brand I'm buying, and think I'm savvy enough to know if the pictures that are up are real. You can never be 100% sure, but that's the down side of buying sight-unseen.