Better idea: Banhammer Scrolls.
They work like this...
First, ban the player and all characters on the account. Roll back any trades or other transactions completed after the incident that led to the ban. Strip their characters naked and lock personal inventory and WH so that nothing can be equipped or consumed, traded, transferred, dropped or sold. Set a 7 day timer on the seal with countdown start after ban is lifted. Any items that are still sealed by the time the 7 day clock expires disappears from inventory and cannot be restored in any fashion. Don't bother with restoration ticket, they won't save you.
Next, introduce new unseal Banhammer Scroll to the L2 Store that allows them to unlock 1 "normal" item for 40,000 Ncoins before the clock runs out. Items that are aggregated like dyes, adena, most materials, spirit/soulshots, etc., are unsealed only one item at a time. For example, if you have 10 EWRs in your inventory, you have to buy 10 Banhammer Scrolls to unseal all of them. Or if you have 500 billion adena in your inventory at time of ban, you will need 500 billion Banhammer Scrolls to unlock all of that adena. "Special" items like Dragon weapons require a Special Banhammer Scroll that costs 120,000 Ncoins, completion of a one-time quest through an NPC, and approximately half the dragon claws and mats necessary to create a standard dragon weapon. Because it's a one-time quest, any subsequent bans means that a player will not be able to restore their "special" items, no matter how many Banhammer unseal scrolls they buy. Oh, by the way, that quest is timed, too. If not completed successfully in an hour, you'll have to wait until the following day to restart the quest again. Don't feel bad. The quest is meant for a full party to finish, but the quest item is totally random and doesn't always drop in the first hour, or second, or 48th hour. Ok, I'll be honest: the quest item drops at such a low rate that a person could farm the quest mobs 24/7 for a month and not get one quest item. Really, really, really, really low odds. But not impossible. Fortunately you only need 5 of them, but the quest items can't be traded and disappear if you don't complete the quest in an hour.
Crazy? Ridiculous? What, are you saying that no banned player will be able to unseal all of their items before they go "POOF!"??? Of course. That's the point. Players would learn not to willingly engage in exploits the hard way. Just one time would be fatal.
But if they do have the money to unseal all of their stuff, NCSoft will be made whole from all of the pricey Banhammer Scroll sales. No more problem of lost revenue. And holiday bonus for GM team would be so nice!