I play a mini version of this at the park with Duncan in the mornings....He is always runing ahead because he is faster than me, obviously!! So sometimes I will hide and he will turn around and come running until he finds me. We did this the other day though and he ran right past me with this terrified look on his face! I felt so guilty I stepped out from behind the tree and called his name. He tried to turn around and come back but he was going so fast, he slide and then I felt even worse!!! So I haven't hid from him since!!!