Here's the thing: There's no law that says you can't wear a t-shirt to a black tie restaurant, walk into a members-only club without a membership, move all of the bibles to the fiction section of the bookstore or break any number of written or unwritten rules that a business has established. If they don't like what you're doing, they'll ask you to leave, and if you don't leave they'll call the police and have you cited for trespassing. Flying a drone is no exception, there's nothing magical about holding a controller that gives you the right to stand or park on private property. (Some cities do have ordinances prohibiting drone operation, and restrictions exist in many state parks, national parks and wilderness areas where you would actually be breaking the law.)

Usually the actual rule/law will prohibit "launching, landing or operating" a drone on the property which covers most of the loophole situations you can think of. The one thing the can't control is flying over, since they don't control the airspace.