jdombrow: the answer is to see if the seller is an actual audiophile, or just a guy selling stuff he buys at rummage sales.
I usually prefer to buy from another audiophile, and not from a reseller.
Another reason to peruse the threads is one can quickly read if a person is arguementative... Helps to know in advance.
Reading the posts is almost as good as a phone call to feel out what sort of person the seller (or buyer) is..