Depends on what info is being shared . Assuming it allowed, last 4 digits of guys phone number would be pretty useful obviously. Various distinguishing elements from screening or maybe ascertained for the bad session. Depends on particulars of course. My sense is that blacklists or whatever you want to call them is to warns about guys who get violent, rip them off, stalk, just very bad behavior etc. The more gossipy stuff (as often is posted here)such as which clients are real ugly or just very bad in bed would overwhelm
any board lol plus for most ladies those aren't showstoppers