I saw some of the clips and it seems pretty random, there's a guy dressed as Spiderman, a guy dressed as what looks like some sort of anime character, and a woman wearing a fancy black gown. There are people around wearing the same kind of stuff without being bothered by the cops, many of whom are filming and taking pics of the arrests. Also, people are just smiling and laughing at what's going on (including the woman in the gown, who turns to the crowd and waves at them with a huge smile on her face as she's put in a police van) so the whole thing really just looks like some people having had a few too many and the cops reacting the way they would in literally any country.