Inactive Users

I had a question about the automatic unregistration of users and SEE

I am implementing a group policy where inactive accounts are removed at 90 days.

If a computer is turned off for 90 days, and a formerly registered user turns it on, are they already de-registered?   Or can SEE only deregister inactive users once booted into windows (so that user will be seen as active today).

I'm worried about scenarios where a computer might be put in a closet for a few months, and then they'll have to call the helpdesk because all the registered accounts have been removed.