One of the main reasons universities/schools block games like wow etc is such games use a lot of bandwidth which the schools are generally paying a lot of money for. Depends on their set up as to whether the network admins can detect exactly which terminals such games are being used at. However if they have such a system as I suggested earlier, this may give them a warning, upon which they might also be able to search the network for such programs if they felt the motivation/need.