Interesting question. Since the laser scope entery doesn't clarify or state a reduction to stealth I would say no it doesn't. I understnd the spirit of the question. If I was the GM I would use the visibility as flavour. The attack missed (Bad role or something) they notice the dot at the last moment and shift, or if my bad guys has one I might allow them a perception to notice the dot to be aware they are in danger. I did use a sniper as an enviromental trap in one mission, anyone left in the open had a chance to be the snipers target.
A laser scope functions as a sniper scope with additional laser targeting capabilities. Activating or deactivating a laser scope is a move action. An active laser scope reduces penalties due to range and AC bonuses from cover by 4. You can add the nightvision capabilities of a nightvision scope to a laser scope for an extra 1,000 credits.