Image by Uncleweed via FlickrBecause something is legal does not automatically make it laudable.
Increase use doesn't necessarily equate to an increase in net harm either.
Set and Setting do define harm risk (a point that prohibitors prefer to overlook). Making cannabis [use] less stigmatized would enable quality epidemiological research.
A patient (or recreational user, practicing preventative early intervention) has a fundamental right to 'informed consent', where fully informed is fully armed and consent is 'self determination'.
I would expect a reported increase in use post ANY prohibitory regime. That should surprise no one.
But at least a little bit of pot sitting somewhere hurting no one will cease to lead to arrest and incarceration and the life long stigma of a conviction for what MOST thinking people believe to be 'of little matter'. (and courts should not deal with such trivialities)