Once you’re at the protest you can talk in person. Sure,. Maybe organizers need some form of communication (and hopefully they do it securely), but otherwise there’s no need. You can just speak with people. People have been protesting far longer than cell phones have existed.

Even people willing to take risks and be martyred should do it in a way that advances the goal. They shouldn’t try to let themselves be tracked and watched/arrested in private away from the protest. If you’re being arrested it should be forced to be in public and made into a show.