I Timothy 2:1-2: First of all, then, I urge that entreaties and prayers, petitions and thanksgivings, be made on behalf of all men, 2 for kings and all who are in authority, so that we may lead a tranquil and quiet life in all godliness and dignity.
This is an exhortation to be in constant pray for the civil magistrate in your area and those who govern the venues where you preach.
There is a promise in the verse: so that we may lead a tranquil and quiet life…..
In other words if you will pray for those in authority they will treat you in a manner that you can live your life without their interference. Since you pray for them as an ally and not an adversary then you will also have a gracious disposition towards the authorities in general.
Also, since the authorities are ministers for God the open air evangelist should have a positive and prayerful attitude towards the authorities including praying for them
See Romans 13:1-7
“Every person is to be in subjection to the governing authorities. For there is no authority except from God, and those which exist are established by God.2 Therefore whoever resists authority has opposed the ordinance of God; and they who have opposed will receive condemnation upon themselves. 3 For rulers are not a cause of fear for good behavior, but for evil. Do you want to have no fear of authority? Do what is good and you will have praise from the same; 4 for it is a minister of God to you for good. But if you do what is evil, be afraid; for it does not bear the sword for nothing; for it is a minister of God, an avenger who brings wrath on the one who practices evil. 5 Therefore it is necessary to be in subjection, not only because of wrath, but also for conscience’ sake. 6 For because of this you also pay taxes, for rulers are servants of God, devoting themselves to this very thing. 7 Render to all what is due them: tax to whom tax is due; custom to whom custom; fear to whom fear; honor to whom honor.”
Thus pray for the Civil Magistrate daily and have an attitude of gratitude and grace towards their presence.