Sherlock wondered why chatting about very real risks was a bad thing, but he quieted down when asked. And kept himself occupied in line by playing with the glow sticks he got.
They ended their brief stint at the carnival by chasing a pickpocket through the crowd. But when they caught the guy, Sherlock deduced the teen was only stealing back his grandfather's watch, which had been taken from him by a few kids at school. So they let him go — at least after Sherlock gave him some tips about terrifying his bullies.