only after rotation and deactivation. we don't have a default policy but we've built everything that's necessary for it. mint deactivates a keyset, and roatates to a new one. wallets detect this and automatically rotate funds to the new keyset when they move their coins. a long time after giving everyone the chance to move, the mint then rugs the old inactive keyset. this is also how the mint keeps its database size constant over a long time period.