Although I only smoked marijuana once and I never inhaled, I am an acquaintance of people who do. People who, I might add, hold down very responsible jobs and pay a large amount in tax. When last in Amsterdam, I went to a "coffee shop" with a friend of mine. I stuck to beer, but my friend bought a pack of pre-rolled joints and smoked one. Absolutely nothing remarkable. There were plenty of other people in the coffee shop at that time of night, many of them American to judge from the accents, and the street outside was packed with people going to and from bars, clubs, restaurants and so forth. Unlike Woking on a Friday night, no-one was fighting, vomiting in the gutters or walking around dressed as a prostitute (in Amsterdam, the prostitutes have their own retail area). In every respect, the coffee shops represent a pragmatic solution to the management of recreational self-medication, which is why it is completely bizarre of the Dutch to institute the new system of residents-only grass.
The plan is that starting from January 1, 2013, people without a special ID will not be allowed to make purchases of cannabis in the city Coffee shops. ID in the size of the credit card with the picture of the owner would be issued at request to all adult inhabitants of Amsterdam, while tourists and visitors to Amsterdam would be excluded from applying for this permit.[From Amsterdam Coffee Shop News 2012 | Amsterdam.info]
I'm surprised that they are allowed to do this under EU Law (what happened to the Single Market?), but even before this moronic edict takes effect, it is already having the entirely predictable consequence.
Unsurprisingly, what has happened is that drug dealers, who previously had dealt only in hard drugs, are now also selling marijuana illegally.[From Freakonomics » Drug Dealers in the Netherlands Now Selling Marijuana]
Why the Dutch want to make Amsterdam more like Woking is completely beyond me but anyway I will make a prediction about it right here right now. Next year, some drug dealers will make more money selling bogus ID cards than they do selling the grass. I sometimes wonder if drug dealers don't have the most effective lobby in Parliament.