No matter what you do, someone will find a way to try to cheat the system...
1. Stand up...simply means you become an "observer" for that table. Someone else may/might take your seat. and you might have to sit somewhere else to get back in the action. Maybe the table even fills up and you can't sit down.
2. Abusive attitude. With ANY site, yes even BrainKing, people can become victims of abusive. Usually verbal (foul language, taunting, etc.). Or even manipulating the rules so they never have to pay a blind or get some other advantage.
At some point, as the tables grow, I would hope the poker tables get a group of "Moderators", just like the other forums. Those encountering abusive players would need a way to "report" the abuse.