^ I've come up with a new nickname for these type of inconsiderate people:
"Tboner's"
I was interested in buying a knife recently, but I noticed it had already been taken.
https://www.bladeforums.com/threads/strider-sng-sold.1699322/#post-19422377
Instead of posting an, "I'll take 2nd's," I just moved on. As it turned out, I contacted the seller the next day (this was 2 weeks ago), asking what happened to the 1st taker, & this was his reply:
"That guy is a thread killer. I lost an entire Friday night of potential buyers to that dumbass. He never responded to any emails requesting payment for the knife. Thankfully I sold it to another buyer. Please put him on blast."
T-boner's habits, of $hitting all over people's sales thread's, instead of taking the time to learn forum etiquette (learning how to send a visitor message, or buy a basic membership), only to disappear & cease communication, has continued.
https://www.bladeforums.com/threads...don-2018-t-e-black-std.1700086/#post-19429640
https://www.bladeforums.com/threads/microtech-ultratech-d-e-otf-od-green.1700296/#post-19443131
I have to agree with the OP, this type of behavior is getting worse here. Personally, I just put these type people on my ignore list, & be done with them. And if somebody on my ignore list ever posts in one of my sales thread's (it has happened). I ignore them. The ignore feature, is my favorite feature/tool, on this forum. 

FWIW: I've never experienced this type of problem over the green forum. The cove is run and moderated very well; they also don't allow any stupid, senseless trolling, or needless crapping in a sales thread.
I have had this happen a few times over on the JD.