Check out the book, "A Five is Against the Law." We've been using it with my 12 year old, because he blurts out threats in an attempt to be funny. He has been suspended due to school policy on the matter, but now he is making the connection that this is a "level 5" behavior that can become a law enforcement issue. The scale is similar to other 5-point scales used for emotional regulation.

There are different types depending on the message you're trying to convey to strangers. We haven't bought any yet. I think that sometime someone may think we have the cards to raise money, pull a scam or try to get of a sticky situation. My 4 year-old daughter isn't that threatening but I worry about things that could happen in the future.

http://www.zazzle.com/autism+businesscards
http://autismidcard.com/
http://www.cafepress.com/+autism+greeting_cards

My husband talked to him and told him that. He said that he doesn't want to go to jail. But I am still scared to take him places. What are Autism cards that you are referring to? I have never heard of that.

You may want to buy the my son has autism cards so at least they aren't thinking you're making up an excuse. I assume your husband had a talk with them but if not it's time. You should tell him point blank if he does that again, he can't go the park, movies or wherever it takes place. Lastly, you should tell him that he could get in trouble with the police as public exposure is a crime.