Vikings: no special testing ability - just some interesting URL hacks and such which Fencer did not put safe guards in.
There use to be other similar bugs awhile back that allowed people to read private fellowships, pawn to get more then their allowed games, allowing tournaments created in other fellowships, plus other things which I helped track down a long time ago for Fencer to put a block on.... but I never spent much time to see what game hacks I could do - since most are obvious when done - except for possible a few new ones they found, which hopefully they sent the details to Fencer so they can block those.