Once again, I am reminded of why I stay out of the BST threads and largely ignore them. They cause too much drama.
For the longest time, after having waded through several pages of said drama, the operational impression I received was that asking relevant questions and clarifications, especially those that would be of interest to the potential buyers were fine, fair, and sensible. For example, someone listed a travel trailer for sale in one of the rare ads I did read and I responded asking if they knew the vehicle weight, which was not part of the post. While I was curious for my own reasons, it was not because I had an interest in buying the trailer as I already have one, but that is the sort of information that is very important when considering a trailer and your ability to tow it. Putting that sort of question in a PM would be pointless. The same kind of thing can be said for asking for pictures of an item listed for sale. The benefit to the buyer pool is clear and this sort of thing shouldn't be relegated to PM only.
While I can see more of a case for suggesting someone correct their posting when they put $55,0000 which is an obvious typo, to me it still falls into the category of legitimate question.
As far as putting work load on the staff, I would recommend that if a BST poster finds a follow up comment questionable or offensive they flag it. If it is indeed an out of bounds comment, then take appropriate action but on the other hand if they're whining about ad stomping for something truly legitimate that their use of the BST section be terminated.