In this last case it became pretty clear when he posted the WTB ad right after passing 50 posts. He was actually posting more than one liners, but wasn't sticking around to reply or otherwise engage if someone replied to him.
And I don't remember the rules telling you to stick around, reply, or otherwise engage.
I understand making someone follow the rules.
But why have them, if they are not going to be good enough?
[video=youtube;3vdcw415OcQ]https://www.youtube.com/watch?v=3vdcw415OcQ[/video]