There\'s a server config command to crank down the loot you get from pirates. Any server which hasn\'t done so isn\'t doing it right.
Anyway, back to OP, you\'re opening a whole new can of worms to do with marking people as criminals for raiding other factions. Beyond just being attacked by the trade guild npc\'s, how far would people take it? Make you freely attackable as a red target by just anybody passing by until you\'ve \"paid enough\" for your crimes?