Knowing your rights as a photographer can be very confusing so I thought I would point you to a couple of good resources to review and consider. If you have other resources that you think would be helpful, then send me an email and I will update the article.
The Gregory Brothers published an informative video on YouTube which I have embedded below for your viewing pleasure.
I have included a link to a downloadable flyer produced by at attorney that I have found helpful.
And, the last link for the article today is via the ACLU, which is always a good source of credible information.