Why? What on Earth could somebody do with a tail number, or a license plate for that matter? If there was any real risk, you'd have the bad guys cruising to the airport to steal tail numbers from planes parked on the tarmac.
I agree it's a bit over the top, nobody "evil" can really do anything with them that will land someone else (a legitimate owner and pilot) in jail. I got tons in photos from airshows and can go get a couple dozen more standing at any given spot along the fence at Van Nuys, Burbank or Camarillo airports.
You really think everyone who does such things plans to be put in jail?
I'd be surprised if you can even call the reporting hotline with a blocked caller ID. Mail them enough letters without a return address and they'll follow it back to the postal employee or box that's closest to the source.