It's really a no win situation though if the boy complies. Newsmax will show footage of a game he plays in as evidence that boys are playing in girls sports, and the idiots who watch will believe it and support even worse politicians and laws.

Could be! I was just commenting that the kid could engage in malicious compliance. Let's see what happens when he exits the girls locker room with wet hair and a towel around his neck.

I don't see what part of that even requires them to use the birth certificate

The law in question doesn't actually mandate that school sports teams must be designated “based on the biological sex of the students who participate” in the sport. If you read the law, it only prohibits biological males from participating in female sports. It does not prohibit biological females from participating in male sports. Quite the contrary, it specifically acknowledges that all students, regardless of sex or gender, are allowed to participate in "boys" sports.

https://codes.findlaw.com/az/title-15-education/az-rev-st-sect-15-120-02/

Any chance this is some malicious compliance?

It could be fear. No one wants a bunch of Karen’s screaming in their face. No one wants to be sued or fired. Maybe this is just someone who thinks they need to protect themselves over the kids they’re responsible for