What if someone hacks it to intentionally blind you?
It's not possible to "hack" more output power into lasers with software changes. Would that it was. You can change the duration of the beam, but you can't pulse the beam without a Q switch in a way that changes the instantaneous power.
Picture your monitor going all white... bright for a sec, but that's about it.
[^] in reality the perceived brightness is somewhat higher than the mean (i.e. a light source that's twice as bright with twice smaller duty cycle appears brighter). I'm not sure how large an effect that is, and whether it has anything to do with pupil size adjustment.
I remember when a CRT monitor would mess up and stop scanning right the white point in the middle was much brighter than the normal brightness, I was always worried it would burn in and would shut off the monitor right away
I'm wondering how is the laser scanned over the retina (probably some MEMS chip). What happens if the beam scanning is suddenly stopped in place, wouldn't you get the whole laser power concentrated in a small dot. And it happens so quickly that you won't have time to react.
There may also be some phantom image effects like we used to have on those old TV monitors. Or like we can have when fixating a picture.
What's probably more insidious would be projecting some very lightly superimposed structure. You probably can induce some unconscious cognitive load or nausea. By decreasing the discomfort for example when the user is looking at an ad, you will increase the effectiveness of the ad.