Not quite. Holding somebody's personal property can, under the circumstances, constitute detention. The question is whether somebody would feel free to leave despite their property being held - for example, if you hold somebody's car keys or wallet and tell them, "You're free to go," it may be possible to argue that under the totality of the circumstances they were in fact detained.
In that case, if you recall, the merchant had the benefit of a statute that, with reasonable cause, authorized them to "detain on the premises in a reasonable manner and for a reasonable time any person who is suspected of shoplifting". Further, although the person's departure was impeded, they were not stopped from departing - they managed to drive away.
Note, I agree with the sentiment that charges against the maintenance worker are unlikely here. (Or, in my humble opinion, "Not going to happen.")
