My thoughts is that if anyone we blacklisted also did not show up in MB searches it might help reduce some impact BOT users may have on the MB. Just remove any account that we have blacklisted form all MB searches.
Now their is no assurance that the same account would be used to post and spam ad's , but I know I have found at least 2 retainers with the same name as a first name on my Blist that have bot like activity on the MB. Not common names, actually random lettering so close enough to draw conclusions. I am sure I could find more if I actually tried to find them.