According to Nevada law, he runs this risk of having violated NRS 493.103, which clearly states:
NRS 493.103 Unmanned aerial vehicles: Action for trespass against owner or operator; exceptions; award of treble damages for injury to person or property; award of attorney’s fees and costs and injunctive relief.
1. Except as otherwise provided in subsection 2, a person who owns or lawfully occupies real property in this State may bring an action for trespass against the owner or operator of an unmanned aerial vehicle that is flown at a height of less than 250 feet over the property if:
(a) The owner or operator of the unmanned aerial vehicle has flown the unmanned aerial vehicle over the property at a height of less than 250 feet on at least one previous occasion; and
(b) The person who owns or occupies the real property notified the owner or operator of the unmanned aerial vehicle that the person did not authorize the flight of the unmanned aerial vehicle over the property at a height of less than 250 feet. For the purposes of this paragraph, a person may place the owner or operator of an unmanned aerial vehicle on notice in the manner prescribed in subsection 2 of NRS 207.200.
2. A person may not bring an action pursuant to subsection 1 if:
(a) The unmanned aerial vehicle is lawfully in the flight path for landing at an airport, airfield or runway.
(b) The unmanned aerial vehicle is in the process of taking off or landing.
(c) The unmanned aerial vehicle was under the lawful operation of:
(1) A law enforcement agency in accordance with NRS 493.112.
(2) A public agency in accordance with NRS 493.115.
(d) The unmanned aerial vehicle was under the lawful operation of a business registered in this State or a land surveyor if:
(1) The operator is licensed or otherwise approved to operate the unmanned aerial vehicle by the Federal Aviation Administration;
(2) The unmanned aerial vehicle is being operated within the scope of the lawful activities of the business or surveyor; and
(3) The operation of the unmanned aerial vehicle does not unreasonably interfere with the existing use of the real property.
3. A plaintiff who prevails in an action for trespass brought pursuant to subsection 1 is entitled to recover treble damages for any injury to the person or the real property as the result of the trespass. In addition to the recovery of damages pursuant to this subsection, a plaintiff may be awarded reasonable attorney’s fees and costs and injunctive relief.
If this is based on the video in this thread, it looks like he was under that 250 ft ceiling. If this was the first time, Tesla is going through law enforcement channels to properly notify the drone operator that they did not authorize the flight. That's detailed in sections 1.a and 1.b. If he flies there again after being notified, that could be considered trespassing as described in NRS. 493.103.
The risk to the drone operator is flying after being told not to by the property owner. I'm not a lawyer, so I have no idea if Tesla could claim damages (building under construction with views of proprietary machinery?), but just getting hit with "reasonable attorney's fees" will be a burden for the average person. Would Tesla actually seek damages? For a one person, seems doubtful (but again, not a lawyer). If enough people go out and do it, then they would have to make an example out of someone just to stop it.
Also note, Nevada does not make a distinction between a private home and a place of business for this trespass law. Doesn't even have to be a building, just property that you own. Also I don't think that the comparison between using a DSLR from a distance off the property and what happened here is not a valid comparison. That's an issue of privacy, which is important but just not applicable to 493.103, which is about trespass.
That is an excellent well reasoned post that really addresses the issues - especially the most important of notice. I assume, as you do, that consistent with the Statute cited the owner was putting the pilot "on notice" that he would seek prosecution for a subsequent offense. I have a question beyond that and any here - lawyers and those that play them on internet forums - can address. Why in the heck is a law enforcement official inquiring as to a CIVIL OFFENSE. In the opening sentence of the Statute it is clearly stated, "...makes it a civil offense..." The OP said he received a call from someone who identified himself as a Nevada law enforcement officer -what proof did he have he was actually talking to who he thought he was. I would be VERY hesitant to take someone's word they were a law enforcement officer over the phone. Ask for a call back and verify this through a phonebook or get the name of the Officer and call the non-emergency number of the Agency and ask to be connected. I call foul on this one and for two reasons, 1) It is a civil offense and no business of law enforcement (they investigate CRIMES) and 2) I would doubt that the OP really talked to a law enforcement officer without further information. IF the OP did violate the statute and IF he has been put on notice and IF he violates the statute again and is called into court (CIVIL) court by the "injured party" I would be very surprised. This is another case of a State passing a stupid law in response to public pressure over fear and ignorance - two things in ample supply. Thank God it's not a criminal offense as it is some places. Best of luck and FLY ON!!!!