For purposes of principle, I ban keyboards from West Toasts since some of them were run on PS2, some on PC, and in the future (if ver.C ever comes out on Arcade/PS2), there won't be any people left behind again. Also, the process to disable certain inputs or to make sure that the keyboard player receives P1/P2 side is, as magz said, a royal pain in the ass, and that's time better spent keeping the tournament running smoothly instead. However, they're allowed for casuals on-site.