In response to the down-votes to my earlier post, what I was trying to say was that the small <5mW finger sized laser pointers that post people might have picked up as curios over the last couple of decades or so are unlikely to be the devices used here. I admit that it is perfectly possible to obtain lasers with much greater power and better collimation than these.
I personally think that the use of lasers over a certain power should be licensed (I thought it was in the UK, but it appears not). Certainly, some of the YouTube videos of people being able to melt quite significant thickness's of plastic (one video shows holes melted in CD cases) using lasers in the 100-200mW range are sobering. And the >1W hand-held lasers really ought to be regarded as seriously dangerous.
Looking at the UK Health and Safety legislation, it looks like using any laser above the MPE (Maximum Permissible Exposure) for the type of laser without the appropriate safeguards is illegal. The booklet HSE95 includes a section on "beam projection at roadways, occupied buildings and into aviation airspace" which defines what is acceptable, and what is likely to be acted upon by the authorities.
I must admit that I used to be interested in seeing how far a laser pointer could be seen from, especially when shone onto road signs (which reflect light back in the direction it came from) until I read this booklet!