Re: Don't be the bad guy
If you guys are going down this route you need to add the works of Rory Miller to your reading list, along with Dave Grossman and Peyton Quinn. It's good to see people discussing self protection, the cultivation thereof, before a situation degenerates to the physical. As I have said before, in military terms physical self defense represents three levels of weapons failure. In civilian terms they are, loss of awareness, inability to avoid, and inability to de-escalate.
Perhaps for those who go this route the final step is escape, or be prepared to explain your actions. Sitting with your back to the wall is good awareness, unless of course the only exit is at the other end. ;-)