So under the rules, if you actually take off or land with somebody standing next to the runway, that's legal. If you make a low pass but don't land, you're technically in violation. I have heard of pilots getting violated for making low passes (even though everybody does it).§ 91.119 Minimum safe altitudes: General.Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes:
(c) Over other than congested areas. An altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those cases, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure.