Well, this is an interesting question.
However, I have two (minimum) armed ushers in every service. They are retired police. I have others who are equally as well trained. I have a special forces soldier, a federal marshall, a retired chief of police, two black belts in Karate....one holds a black belt in 3 diciplines.......and then there is Nannie......my mom... she would just love them do death....
Seriously, we would look the doors to prevent them from leaving. If you come to service, you have to stay....

We would "detain" them until the authorities arrived and they will be charged with disturbing public worship. If they come in quietly and are respectfull of the house of God, they are welcome to stay. If they (or any one ) tries to disrupt, they will be charged. We don't go to the gay clubs and barge in and start preaching.
We do have a plan.
Dr. Ron