I agree. Redsec is probably one of the more enjoyable modes I've played. Every multiplayer game mode it too easy. The majority of games I've played on multiplayer consist of players that just feed, don't know how to defend, etc (thus too easy). I've found redsec to be the only mode where I have to actually be more map aware and think when/how to engage. I would expand your idea and say make the penalty so that they have can't join in any game, including multiplayer. It pretty clear a person that leaves the redsec game would just try to play another mode if the penalty was actually implemented, so adding that penalty across all modes would be better.