emmett: I would not worry about having someone play from the same computer - as long as there is not something very obvious (like many many games in short time with 1 person resigning or purposely losing, etc...) - otherwise I don't think Fencer pays attention.

I know he keeps track of IP and such, but 2 players with same IP alone is not something that should cause you problems on this site (others game sites, possibly... but not here)