This older gentleman and his wife had been staying in room 120 for a couple of days already and were on their last day. Sometime after housekeeping was done for the day, they left for a couple of hours.
About 10:00pm (and luckily afte rmy GM had taken over for me) the gentleman walks into the front office handing us a key in it's envelope. He said that it was on the bathroom counter. 123 had been written in the room space.
At first we just thought maybe housekeeping accidently left it there but then the man explained they had already been there for a couple of days. My GM and I were pretty sure that maybe they just accidently sent it down while cleaning.
He was insistant on the fact that he and his wife were in their room for a couple hours after housekeeping was done. They then leave for dinner and a few things and when they came back, it was there.
My GM and I calmly explained that had someone opened the door to 120 with that key then their keys would have been de-activated. But since they didn't have a problem getting back in their room we were sure the it was left there by mistake and he must have not noticed.
He was SURE it wasn't there when they left. After about 10 minutes he said he understand about how it would make their keys not work. I thought it was finally over.
Even though he understoond about the keys, he wanted to know how that key got in his room. He was SURE he didn't overlook it. This man was not going to leave until we gave him an answer. I finally had to walk out because I was wanting to reach over the counter and starangle the living crud out of him.
I have NEVER had anyone sit and argue that long and that hard over something a) obviously simple to solve and b) didn't cause any harm to anyone.