That is classic!
Reminds me of the time my aunt was out here to visit a few years ago - we have a very, 'our house is your house' approach to her visits so she thought nothing of making herself some peanut butter toast one morning while I was showering. I came out to the kitchen, saw her eating her toast and then saw the peanut butter jar on the counter......it was the one I use for the dogs' kongs, and since I only use that jar for the dogs I never worry about letting them lick from the spoon, double dipping, etc so there is/was dog slobbers in the peanut butter still in the jar..........I couldn't bring myself to tell her, but I did hide that jar for the duration of her visit and made sure the "people peanut butter" was what was front and center where she'd find it.