I made a big 7-layer taco dip thingy to take to movie night at a friend's house. Because a couple of people in our circle are vegetarians, I also made a smaller casserole of the same dip, without the meat. Anyway, people loved it, particularly my vegetarian friend who was really happy that someone had made something special for her.
When I got home and was cleaning up, I realized that I had used the can of traditional refried beans, not the can of veggie ones. And when I looked on the ingredients, LARD.
So do I tell her, or not? She's not allergic to meat, so it won't hurt her, but she has been a vegetarian for 20+ years and I know she'll be upset. On one hand, she has a right to know, on the other hand, it will really upset her, and it's something that can't be changed now.