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These high-power ( > 1mW ) green laser devices are actually far too powerful to be used as 'pointers' in presentations or lectures, as they are so powerful! The reflected light energy is blinding to the presenter!! (similar to the effect on the road signs mentioned).
I'm not sure of their initial concieved use, be it military or otherwise but I do know they have found a use within the amateur astronomy circuit .where they were used as 'star pointers' (to align telescopes and to point out stars to others). They are falling out of favour however, due to the issues surrounding pilot blinding incidents.
The only real way to stop this IMHO, would be to reclassify any laser pointer with a power output > 5 mW as a form of potentially offensive weapon, perhaps introducing a licencing scheme such as exists for firearms to allow for legitimate uses.
For more info than you could possibly want on lasers, see
Sam's Laser FAQ: Welcome Page