Recently advertisers seem to be using large lasers to draw crowds to a sale or special event, because the general public wants to see how bright a large laser is so they will drive a long way to see one.
The danger for a pilot is if you are hit with the laser you may be temporarally blinded, so you should avoid these areas where someone is using a large laser (usually it is a green beam laser). Normally the user has to receive approval and have a notam issued, and they are usually restricted as to the height and direction that the beam is allowed to be pointed.
Either way, you don't want to look directly at a laser or a large spot light while flying.
Mike
NATCA FWA