I have an 8 month old DD and I'm constantly surprised by things people think are acceptable behaviour. This is possibly 90% aimed at my MIL but I find people think it's ok to stick fingers in a child's mouth, or put child's fingers in their mouth, and generally poke, prod, stroke, clap at and annoy.
So, would it be unreasonable to counteract this by any behaviours I don't think it appropriate, doing it back to the person? Today this would have meant thrusting my dirty slipper in my MIL's face and then gently pushing her in the chest with a dirty slipper covered foot while she tries to put her shoes on? I think it's the way forwards, right?