I made a purchase shortly after joining the board that I did not realize (it wasn't super clear in the post) was a presale of books still at CGC. I was not aware until 2 weeks later I asked where my books were, only to find out that for some strange reason they were still at CGC. It was almost a month after I paid until I got my book. The seller is a great seller and I still purchase from them but I don't pay now until the book is in the sellers hand.
Anyway, it was something I learned to watch for, and I do not think I would pre-pay like that again.