Answer:
This is hard to answer because people have different opinions. I BELIEVE that they should be arrested, but this could differ between people. The Westboro Baptist Church is a great example for this dilemma. They protest veterans and homosexual's funerals, holding up signs that say they are going to Hell. No one has been arrested for doing so, as it is an American right to protest.
THE POLICE ARE NOT GOING TO ARREST THEM UNLESS THEY ARE BEING A PUBLIC DISTURBANCE (being loud) OR UNLESS THEY HURT SOMEONE (physically).