Nicholas: What are we having for dessert?
Me: Let's wait and see.
Hubby's Sister: *puts out a large bowl of fruit salad on the table*
Me (brightly, sensing impending disaster): Oh, look, Simon, fruit! You love fruit!
Simon: Yay, fruit!
Nicholas (looking bemused): What else is there?
Me: There's lots of lovely fruit here. We don't need anything else.
Nicholas (turning to his father for help): Can we stop and get something on the way home?
Fortunately my husband's sister is a good sport, and has kids of her own, and didn't seem to take it amiss. But once we got back in the van I took pains to explain to both boys, gently but firmly, that there are things you do not say when you are a guest at someone else's table...