(At the aquarium where I volunteer, a guest sticks her whole hand in our touch tank, rips off a sea urchin and proceeds to stuff it in her bag.)

Me: “Excuse me, ma’am, but you can’t do that.”

Guest: “What do you mean?”

Me: “You can’t rip the urchin off the tank’s wall. Could you please hand me it?”

Guest: “But I was going to take it home and eat it. Isn’t that okay?”