Well, like I said, I've heard of LANs having successful Starcraft 2 tournaments despite the lack of an actual LAN mode. I don't know for sure, but I would assume that Starcraft 2 uses less bandwidth than a FPS. Especially Bad Company 2, with all of that building destruction going on.
I think at the very beginning of the LAN we should run test games to see how it works, and if we don't experience any problems, then a tournament should happen.