[Plain Old Jane]

well theres also the recognition of the wrong doing, and the fact that (hopefully) you are not smoking pot.

if your neighbor smokes pot and you see it once, you could just close your blinds and completely forget that you saw it, or what is (small chance) that the gentleman is a major player in the trade, you could end up dead if you report him so how could you get in trouble for being afraid to get killed.

I sort of see a parrelel in this kiddio porn thing. if its a pop up or something your friend wonko sent you, then you just close it forget you ever saw it and if you're paranoid, get a disc true deleter (one that rewrite all the zeros and ones back to zero or random, in some cases up to 32 times where unless the NSA wanted to know what was on your HDD, they cant really get you.)

If you save if to your hard drive or smoke up with your neighbor, than you are accountable. In major crimes I can see the use of it, but in minor ones it just hurts the innocent and afraid. Smoking weed should not be a crime IMO.