yes but he can log in again and change it again...
How?
=squeak=
edit: to change withdrawal address, you have to sign something using your address (as I understand the procedure). once the withdrawal address is changed to whoever the account is being sold to, then changes made to the account from that point, can only be done by signing with the new address.
Current situation:
Log in: deposit address
Payout: payout address
So after changing the payout address, the new log in address is the new payout address instead of the deposit address it was before that?
New situation:
Log in: new payout address
Payout: new payout address
That is how I understand your comment, but I haven't heard this before and it isn't mentioned anywhere as far as I've seen.