California had a private property/airspace/public land type confrontation a few years ago that demonstrated how it all works.
The property in question was the cattle feed yards near Coalinga, which was, and still is, the subject of animal rights groups focus. The operators were flying from the easement of a state highway which had few rules prohibiting trespass or drone operation. The operators were flying over the cattle yards and filming conditions, which generated a lot of anger from the property owners. The property owners contacted state and local police agencies, who responded in force to terminate flight activities. We can surmise a few “paid for” politicians also got an ear full.
The drone operators were up on their game and had researched property and airspace laws and because of this were successful in showing the numerous law enforcement personnel they were not violating any law, and that in fact the property owners were attempting to abridge the rights of the drone operators by using law enforcement to illegally prevent their free access to navigable airspace.
When all was said and done the operators fulfilled their mission, although law enforcement was present for the duration in case a chargeable offense was committed they could be cited for. A tense situation but one of the better examples of how knowing the law and having the proof of law in hand benefits an operator greatly.
Having a few people on hand to record the ground confrontation for public dissemination was also extremely helpful.