I love hosting family gatherings and often do so. My SIL is vegan and I don't mind taking extra care for her dinner, not hard work anyway.
Twice a year I boil two kg of chickpeas and make hummous, most of it with yoghurt to make it low fat, and some with tahini. Then I freeze it in small portions, sometimes for us and I often serve it at dinner parties.
You canobviously see where this is going, last weekend I served SIL what I thought was vetgan tahini, and this morning I went to the freezer to get some of the yoghurt kind but it was all gone... I have no idea how I mixed it up. I also now remember her going more than once "your hunnous is really yummy tonight, you should give me the new recipe". I said there's no new recipe and she insisted "no, I know your hunnous, it's always good but you've done something special to it tonight".
It all makes sense now... I think I shouldn't tell her... I mean, what's the point? 
AIBU?