It would also presumably mean that the government could compile a list of cellphones that turned off during the protests, while not located at but rather near t

It would also presumably mean that the government could compile a list of cellphones that turned off during the protests, while not located at but rather near the protests. To a sane government, this information wouldn't be of much use. To a crazed paranoid government going on purges and witchhunts, this could be all the information they 'need' to find somebody suspect. Of course if you pull the battery, they would also notice the phone dropping off the network (though it would be unclear what the cause was). To a crazed government, the difference might not be too important. If you are ever in the sort of situation where any of this might become a concern, I recommend leaving the phone at home, sitting comfortably on your couch, turned on with the TV on. Of course this precludes using the phone in an emergency, so 'burner' phones with removable batteries may become valued.