So did the GM do good?

The spot thing doesn't make much sense to me unless of course the person was still on the account when the GM told him he needed to get on it like sapta said happen to her and the person told the GM his concern about losing the spot (maybe even telling him he paid for it) so the GM had little choice but to try to secure the spot till the issue was resolved, though how the GM would contact the person after being done to give back the spot confuses me.

I don't think the GM would have gotten on the person's account if they'd said "but I don't want to lose my spot." He'd have just moved on to another ticket and gotten back to that guy at some other time.
BTW, when Atquei wanted to get on my account he just d/ced me. He claims he whispered me first, and since I didn't answer he assumed I was AFK. So if this person set up shop and went AFK, Atquei might have done the same to him - and then when he logged in and found himself in FM he realized the problem.
I guess they have instructions to leave characters exactly as they found them after such "investigations" (unless they find something amiss, obviously), so he wanted to put the shop back up.