Just had my first negative experience with the authentication process...
Bought a pair last night through an offer that the seller sent. The listing had the authentication badge and everything. After checking the tracking, I noticed that it's being sent to me and not eBay first. I call eBay just to get an explanation on why it's not being authenticated and was told that because the shoes were sold by best offer and not buy it now, that voids the authentication process. I then told them that that didn't make sense because another pair that I bought on the same day was bought through an offer and it is being sent for authentication. Then I was told well it's just an error on their end and sometimes sales with offers work and sometimes they don't.
Sounds to me like they just don't know what the hell happened and didn't want to say that. Thankfully, I am not worried that the shoes are fake, but it's still not a good sign.