Do not under any circumstances bring your cell phone, dumb or not, to a protest.
Memorize important numbers, writing them in your arm if necessary.
Answer all questions with “I assert my fifth amendment right and will not answer any further questions without my attorney.”
The trick that the Government has learned is that it’s easier and cheaper to buy your location data from a third party.
No warrant necessarily since the data is available to anyone who wants to buy it.