Every year I must re-post this because the times they-are-a-changing. Have you noticed?
If you are regularly sharing your faith, sooner or later you will be hassled by people with badges, especially if you are an open air preacher. I found a great 12-point list of what to do—and what not to do—when confronted by the police. Copy this and memorize the protocols… before it’s too late!

1. Always speak in a professional manner. “Yes Sir, No Sir” is an absolute rule. No Street Preacher serves a righteous cause in being publicly rude to an officer. Your attitude will go on the report and will meet with the same disrespect. Read the rest by clicking here.
[...] I encourage you to look up the city ordinances for where you’re going. print them out and have them ready, calmly and peacefully explain that your not trying to get money, donations, or selling anything, have the law printed out, and show it to them… you can find a great article on how to deal with the police over here… [...]