I remember that there was some protest survival guide, and it mentioned to either leave the smartphone at home, or bring a dumb phone w/o contract, so you can at least call an ambulance if need be.
There are hundreds of reasons for not bringing a smartphone, not only the abuse of companies like Mobilewalla. Imagine if you happen to be close to a storefront that is vandalized or a statue that is brought down - cellphone data will make you a terrorist suspect! (At least in the current US).
But that was the stated justification. The real purpose of the report is to advertise what Mobilewalla does. I consider this a form of profiteering.
Which is just a piece of paper. It has absolutely no power to protect you. Only a government that respects it can do that, and it's a certainty that our government will, from time to time, completely disregard that document when it feels the need to.
People have good rational reasons for hiding all sorts of legal activities they participate in.
To put it another way: you can't rely on the Constitution to protect you during a protest against violations of the Constitution.
Or imagine a left wing authoritarian government targeting lockdown protestors.
We should all be concerned about wanton data collection.