Am I missing something? That video is so short it's almost impossible to tell the context. It could be a joke for all I know. The fan seems to be playing along and happy and the video cuts off when the situation would seem to tell a more detailed story.
How are you deducing that the fan is happy and playing along with it after they grab her throat? Yes she's smiling and cheerful prior to the choke, but it goes chokehold to take down, with the people recording then going "woah!"