I know it does not work like that!
BUT MARK IT! MARK IT FOR THE HELL!
I ignored the word "account", but I'll explain it anyway: Bitcoin doesn't have "accounts", only addresses. There's nothing to mark. The only way to do that would be through a hard fork that marks this specific address as "do not use", and that goes against everything Bitcoin stands for.
Bitcoin is irreversible
by design, it's not a shortcoming, it's intentional.
Yeah and the silkroad money was tagged and observed. Noone does that if you know that the coins are stollen... LOL