So partner and I have recently bought a house in a town nearby to my parents.
Prior to buying to house my DM didn't know the seller but in the process of buying got really really chummy with them and helped them move and clear the house.
We think in this time my DM managed to obtain a spare key. There was only one set of keys declared and that's all we received from the seller. But there was a niggling feeling in my gut about it. My DM hasn't done this before specifically but she has form for other, similar behaviour. Not something I could outwardly ask her about either.
At a recent family gathering someone else brought up the topic of ring cameras and how they have one at home for the dog when they leave her for a short while. I brought up that we'd just purchased a ring doorbell for ours.
Cue a very angry 'well why on earth would you want one of those!' from my DM.
I explained to the group that we'd only received one set of keys when we'd bought the house and I felt like another set of keys could have been left with someone else by mistake (the seller had lived here for an awfully long time). I explained I felt uncomfortable with this as did my partner so we'd bought the doorbell just incase. (We do also receive a very high volume of packages as I use a room in the house as storage for my business).
I don't think I've ever seen my DM in such a silent rage before. And I have quite frankly taken this as proof that she's done exactly what we thought and managed to get a set of keys for our house!
AIBU- she hasn't got a spare
YANBU- she's definitely got a spare key