BOTs can only go up to 15 (unless you use that mutator TEAM-something). For 400 people? Wich server would run this world (not saying is a
bad idea), with potencial for 200+ players?
Too heavy a map. Too heavy a player number...
And... things would have to be done with LOTS of eye barriers. That or monstruous lagg.
Back to player issue, when you have less people (or BOTs) on a server, you'll spend the better part of the on-line time just looking around por a target. The concept is tempting (EPIC was to do it with Unreal 1, back then), but it would not work. Especially with less people playing UT these days. 400 = UT community
This was suggested before, don't remember where...