With all due respect I do not agree with your solution or agreement. It in effects limits the scope of play by forcing you to behave legally and handicaps any player that wishes to experience life as a pirate. It's already hard enough to be a pirate in that you are forced to pay off your debts upon death without compounding that onto an alt.
Piracy should be making enough money to pay off that stuff AND have money to spare if it's working as it should alongside the other professions. Repeated mindless killing would be the one where your debts/bounties rose to more than you could pay off.
As for not wanting to tie that to an account, I can understand the desire not to do that. So another way might be to make it that you simply cannot delete a character that is in debt. If someone racks up huge bounties through griefing, for example, they get the standard in-game consequences, but they also cannot just delete and start again. Until they've paid off the character's debt/bounty that character remains in play - no delete. Someone wants to play just to PK for no in-game reason then their 3 character slots will all be screwed in fairly short order.