Many moons ago an ex-colleague of mine got a Police chopper to go after a zone intruder and identify it. His actions were frowned upon because there was no guarantee what the "wildy" would do next and a mid-air with a Police chopper would not go down a bundle! This is not something which happens too often but intruders are tracked on radar with a fair degree of success... Problem is, very little happens thereafter apart from a gentle slap on the wrist.