I missed the postie yesterday and have been left a card.
I don't know for sure, but I suspect it's something from vindictive MIL (she has form).
If I just leave it and it turns out it was something important, what happens?
Once previously, one of her signed for letters was just put through the letter box and the tracking marked signed for, which didn't matter at the time because it was safely delivered, but I'm concerned she'll think I have something I don't. Or that someone else whose mail genuinely is important will think it's been delivered.