Two great posts on fair use and clearance rights on the Stay Free! Blog. The first is an interview with the director of the favorably-reviewed documentary Mad Hot Ballroom, which is about public school kids in ballroom dance competitions. The interview goes into many of the headaches that citizen creators face if they want to distribute video of scenes of real life (How did Mad Hot Ballroom Survive the Copyright Cartel?).

[W]e had to watch out for billboards and Frito-Lay trucks all the time. But I usually didn't care, we would just shoot. The biggest danger with clearances is when they interfere with documenting real life. Something spontaneous like a cell phone ringing is different than a planned event. If filmmakers have to worry about these things, documentaries will cease to be documentaries! What happens when the girls go shopping and there's music playing in the stores? We were lucky because in our movie the music wasn't identifiable, but otherwise what are we supposed to do: walk up to the store manager and say, "Excuse me but can you turn off your radio?"