Actually, if you are in a public location, you can readily be filmed / photographed without your permission OR your consent. There are two places you can not be legally filmed / photographed and that is INSIDE your own house, and inside a public bathroom.
Anything other than those two spots, you're in public. You have zero privacy laws / rights in a public space. As long as you aren't trying to SELL images of people, it's 100% legal for you to take and post images of strangers without their consent / permission. Look it up.