[RonF]

I wonder about that. There are certainly enough parents that would complain to a school administration if they kid came home with a skinned knee or complaining that they never win a tag game.

[Austin Willard Wright]

Parents have always been like that, at least to some extent. The big change in the last few decades is that the overprotective parent (once dismissed by society as the creator of "mama's boys") is now being reinforced and legitimized by PC administrators. In any case, the principal in this case apparently did not enact the ban because of parental complaints but for her own ideological reasons and because some children allegedly complained.