I'm not sure exactly what accounts you have in mind, but general I would lock them all, no matter what. You may trust them to not retaliate, but do you trust them to have chosen a password that they didn't use anywhere else and didn't get keylogged and didn't give to phishers, and that their account will not be compromised in any other way?
Maybe email is tricky, since they could potentially have some personal stuff they want to retrieve. Perhaps the helpdesk can assist them in that case; or give them 5 days or so where they can still access email.
(If it matters, I have zero experience in this, just an interest in security.)
Edit: I now see you probably meant just giving something like the rest of the day on the lock, if you trust them.