Once the phone is on, they can tie it to a person with geolocation. Either directly if you do it at home, or indirectly when traveling in a vehicle associated with you.

The rule is that you don’t use your burner phone at home, you use it when you are at the protest.

If you have two phones both turned on and they both move around similarly, they can be associated later.

They also tell you to keep one off until you get to the place. Never have both phones on at the same time.

This is all well documented

https://www.offgridweb.com/preparation/burner-phone-basics-h...

This is advice for a world that doesn’t exist any more and hasn’t for a long time. The only thing you are going to do following this advice is to stand out immediately amongst a sea of data that you are someone who is taking very unusual security measures and worthy of a closer look. It’s a very easy to identify signature and it’s very literally the opposite of what you should be doing in 2025.

Buy a burner phone with cash without taking your main phone and stash it somewhere. Then, before protest, take phone from stash and bring it with you

Sure the phone can't be tied to a person. But try getting phone service in the US without giving away your identity. Can't be done.

While true, I'm kinda wondering if that's even possible ...