Fwiw the show I saw was in a closed arena. I actually wish the roof had been open as the closed roof acoustics were awful, but you can imagine why they want to eliminate weather as a factor.

I wouldn't be surprised if concerts have anti-drone countermeasures in place already, given safety concerns.

Like what? This isn’t a battlefield, the FCC isn’t going to let them do any jamming and they sure as hell aren’t putting up CIWS cannons all over the place.

I've seen multiple NFL games be stopped in the middle because of one person flying a drone. They take this stuff extremely seriously - I wouldn't be surprised if the entire concert was put on hold until the drone was stopped. The people who have done this have served jail time and been hit with 6 figure fines.

Oh… drones are a really devious idea. You can imagine all sorts of political messages that someone may want to leverage an event like this to broadcast.

Flying a drone over a major concert is liable to get you charged with terrorism somehow even if you're just trying to do a prank.

Doesn't need to be big enough to scare people that badly.

You could sneak a heap of something like this into any big concert venue pretty easily:

https://www.aliexpress.com/item/1005004496779816.html

open them up and switch out the visible light LEDs for modulated IR ones, add a tiny microcontroller to send pre programmed data. Get you and a dozen friends to launch them all at the same time...