They are there, they are everywhere. You are bound to run into them, especially when traveling to other venues away from your FLGS. The person who is annoying, a bad player, someone who is prone to flip tables for the strangest reasons.
I play for fun, and an experience can be ruined by a player who is out to nitpick every little thing and try to squeeze out every advantage he can, up to the point of blatantly cheating with the excuse of incompetence, stupidity or ignorance.
I have also Officiated some miniature games on the National and worlds levels.
I have already looked at how easy it would be to remove some more detrimental Criticals from my Damage deck, or even replace some cards. the manuver tool does have a little play and i can see someone "flexing" it a bit to get a few degree's more on a turn. and the simplest is putting some markers, or alterations on the range ruler
any other things we as a community should be aware of and maybe look out for?