It’s almost strictly better to leave your phone home in that sort of circumstance though. Your phone looks like you stayed home all day, and you don’t need to worry about things like whether any information gets sent out despite being “off”.
Sure, but if you really want to, you can communicate and coordinate. I know it might sound old and all, but before the mobile phones and pagers, people managed to communicate and coordinate. Admittedly it is not as easy, but it is possible.
It might actually be a good thing to try, and to step back without a mobile phone and unclutter our current model of communication and coordination. It would likely involve more commitments (e.g. "we said that we would meet at that space and time") and less distraction.
I think you would have to leave your phone home a lot more often than on days you don’t want to be nailed to where you are.
Imagine a case where evidence puts you near a protest or crime scene while your phone is home. That’s coincidence, but if your phone also was home only at the three days three similar events happened, it becomes circumstantial evidence.
Most of the time protests in America only start involving law breaking, riot police and mass arrests after the sun goes down. I’d never endorse perjury, but an argument of “I decided to spend the evening inside” seems like it ought to be pretty reasonable for most people.