Marked cards, FtV
Me: “So, what made you notice the card - i.e., how is it marked?”
Player: “Oh, I don't know that it's marked, but aren't ALL FtV foils marked?”
Me: “…”
I cringe every time I see this - essentially, it's prejudice against certain Magic cards, and players seize onto things like this with a surprising amount of passion. And once this takes root in the player community, Judges get to deal with situations exactly like this.
That conversation might continue like this:
Me: “Oh, you didn't notice any sort of marking before he played that card?”
P: “well, no … but…”
Me: “Let's take a quick look at the library” (as I look at each side of the deck, on the table) “do you see any obvious bends, or other marks? I sure don't.”
P: “well, no … but…”
Me: “OK, then, I think we're fine here. If you notice something obvious with a player's deck, please get us involved immediately.” (and, to the FtV player) “please be aware that some foils get a bend or curl faster than non-foils; you should probably check your cards between every match, at least, to make sure that's not happening.”
In this way, we can (hopefully) help the players understand, it's not reputation that makes a card “marked” - only the actual occurrence of markings matters.
d:^D