It's hard enough to master the technical and artistic aspects of video-graphy and film-making to then have to worry about legal rights. But as you know, it's critical.
Here's a brief, easy to follow breakdown of what your rights are for doing photography in public:
A brief but comprehensive rights for doing photography in public - PDF file
Photographer's Guide to Privacy , including a state-by-state guide
And a rather enjoyable, and thorough USA Today article on the subject that refers to other resources as well.