They camp a lot, if You are playing de_dust2 for example - they have couple of camp waypoints near one of bombsites. We do have that flag for waypoints as camp waypoint. Read docs - the chapter about waypointing.
Invisibility probably will be not working for bots (they will see You), because they don't check the player's rendering, so the tracelines can hit such players still as well - so for them such players are "visible"