Police aircraft carry spectrographs that can give a very good idea of whether the l@ser the scrote is arrested with is the one that was shone at the aircraft, if everyone has the time and inclination
Are you sure about that? Do you a have a reference for the spectrographs carried by the police aircraft?
For example, the very common green 532 nm DPSS lasers put most of their power into a very narrow spectral line which I would think would be hard to use to tag individual units. These lasers are frequency doubled and diode pumped in infrared but most models attempt to filter out the pumping 808 nm and 1064 nm frequencies.
I guess you could try to generate a signature from the ratio of the three frequencies but somehow I'm not sure that would convince a judge that only a particular laser could be the culprit.
Lasers can be intentionally modulated with a code for identification of the beam as in the LANTIRN targeting system for the F-16.
Anyway, the feds are on the case at LGA:
FBI Investigating Following Recent Laser Attacks On Pilots « CBS New York
“Laser pointers can be extremely destructive,” said CBS News aviation and transportation safety analyst Mark Rosenker, also a former head of the NTSB. “They don’t realize that the actual beam itself can be magnified going through the cockpit glass.”
Gee, I didn't know the cockpit glass could magnify the laser beam...
