Shoe Woes

When I picked J up from JK today the teacher told me, yet again that "he likes to throw his shoes". I know I should take it seriously (I guess?) but everytime she says it I want to laugh. Side splitting, totally inappropriate laughter. Of course it's not ok, of course it drives me crazy when he does it at home, of course I remind him each day "and we don't throw our shoes up in the air". Today when she told me he said, very seriously, to her "I know Ms. T! Next time I come to JK I promise I won't throw my shoes" she said "It's a deal" and they shook on it. So why don't I feel reassured that it won't indeed keep happening?