@SmileAtmysins - More often than not, those posts your talking about aren't asking for the member to be banned. Except for reporting spammers and scammers, most of the time what you'll see is observations that a member is heading in that direction if he doesn't change his ways. It a little like watching a train wreck. Some times we'll try to give the member a heads up, that the person is heading for a ban, but except in extreme cases there's really no need to even bother the mods about it. They see the same new posts as the rest of us, and they'll come across the threads in due time.
Once the mods come across a thread they usually give the guy a chance, and don't ban him until after he ignores their suggestions. It's not a perfect system, but voting for bans would just turn membership into a popularity contest.
edit -
Harro started a thread a few weeks ago asking members to vote on having a mass un-ban. That was due to a different situation. There were a lot of members who's accounts had been compromised which resulted in a lot of accounts being banned. But that was an esceptional circumstance so they asked for a vote just to get everyones input. That thread wasn't about voting for any specific members, even though a few members took it to mean that.
I made a suggestion in that thread that I still think was a good idea. That is to have a SHUN level that mods can put a member in before giving an outright BAN. Hopefully they are giving that thought some consideration, but changes like that involve a lot of work so I wouldn't expect to see any changes for awhile.
It would be nice if the mods would use the Banned Members subforum a little more often when they ban a member. Or maybe post a message on the members public profile about if its a temp ban or permanent ban. The mods are already spending a lot of time trying to keep the forums running smoothly, so I guess it just seems like more trouble than it's worth to post an additional message.
