Used to do a similar thing at my nans as a kid – but throwing used teabags at passers by. She happenes to live right next to the main rear entrance to the shopping centre so there was always a lot of human traffic. Once I remember it landing ina pram and some poor kid got battered for playing with it LOL. On the odd occasion we lobbed water bombs too – I remember hitting a bald guy on the top of his head but the balloon didn’t burst and bounced off :O She didn’t live too high up so it wasn’t reall that dangerous, but it was fun!