The Law: no expectation of privacy in public. Start looking for cameras every where you go...you will see them. You don’t have to tell anyone. You could get your girlfriend to walk in front of you sometimes. And buy some pepper spray,
True, but only part of the equation. Using another person's likeness for commercial gain without their permission can be highly problematic. So, if he's interviewing people on the trail, or just recording their antics no issue. It's when those videos get posted to a monetized YouTube channel and the poster gets paid without the consent of the recorded third party there could, and inevitably will be, letters from lawyers.