Can't disagree with what you wrote on your blog. Personally, I would never buy a cake without sampling. It's roulette, the Russian kind. But, if a vendor I knew recommended something to me, I would give him my checklist and if the tea passed, I would consider buying the cake. But all the good vendors I know sell samples!
The other point is the poor quality of some samples that have not been cared for over time and don't reflect the quality of the actual cake. For me, if the seller doesn't pay any attention to their samples, I wouldn't bother with them. This might make me miss something good, but I like my chances without them.
One of the biggest suppliers for many of the posters on this board is a big offender in this area. I have had more bad quality samples from them than anyone else. Many smoky teas that are not described as such, especially Xiaguan.