What could the authorities do if someone flew a drone over a sporting event?

They'll send up their antidrone and take yours out.

I'd say it probably depends on where the drone is in relation to the sporting event.

Taking overhead video of the crowd from outside or high above the stadium? I've seen people do this before and it's not really an issue; plus it's not like they're gonna shoot at a tiny thing high up in the sky, endangering the crowd in the process.

Hovering just over the crowd or the field and they'd probably shut it down once they found you.

EMP cannon to the dome

Probably nothing.

If it went down, they would just take it. If not, then nothing. I mean, they aren’t really trackable on a radar

There are several companies marketing anti-drone devices to the military ever since ISIS started strapping explosives to the things. Only a matter of time before law enforcement has them deployed at large events. FWIW, they have ballistic ones but also ones that are a directed radio beam and basically scramble the signals and make the drone fall out of the sky.

The pet food woman in Baton Rouge is probably up to date on the latest anti-drone technology. She was targeted this summer during the protest. “ they had drones outside of my house for a week “

Get arrested. LINK university Kentucky arrested flying drone