With as many people who use this plant world wide, nevermind just in the states, they're more concerned with people who may be getting wealthy off the sale of "contraband" than some 18-24 year old growing 3 plants in a closet with CFL's.
That is pretty much the common belief amongst most growers I have talked with. But my experience with the police has been a little contrary to that.
Basically if you live in a city in most western countries, there will be a division of the police called something like, 'the organised crime unit' and within that division will be teams that specialise in the different facets of organised crime. Some of them are obvious, the meth manufacture division, white collar fraud squads etc. But they will also have a team or person, depending on the size of your city, working marijuana grow ops.
These days it is seen as a lesser evil than the harder drugs like crack and heroin, so they tend to be less human resourced and less financially resourced too. But nevertheless they are dedicated to what they do and make do with what have.
Also under this organised crime unit will be specialist teams like teams that can place interception devices, high level survellience, e-crimes etc. They are available to be used by any of the sub depts of the crimes unit, including the under manned under funded marijuana team.
The way they do it in this country is to manufacture the idea of drug networks. By using this technique they can get around the whole 'why are you wasting your time busting small time growers' thing.
A recent raid in the northern part of this country is a case in point on that issue. The drug squad in that small city had been monitoring the incoming and outgoing of a hydroponic store. They collected data on all those buying grow gear and also looked into who knew who.
Being a fairly small city, a few of the growers did know each other outside of buying from the same store.
With a flick of the pen they were able to conjure up a network of growers out of mere aquaintances, opened an 'operation' against them, which gave them the funding to do all the bullshit they do to create the grounds for the eventual raid.
The raid was carried out and the item on the radio said something like, "Drug ring busted wide open when police stormed dozens of grow houses in the early hours of this morning finding over 100 plants and resulting in the arrest of 17 suspected cannabis cultivators".
Because one of the arrested was a member of a local gang, they also threw in the gang connection line too to spice it up.
Most of the plants were found in 2 houses, the rest were small time growers who had 1-4 plants. Most of the arrested barely knew each other and werent growing to sell. But who is going to argue with the police notion of a so called 'drug ring', or terms like, 'sophisticated grow room'.
Age also, has nothing to do with their decision making, whether youre 18 or 80. Nor does gender. Most of those arrested were female so the police simply constructed the idea of a female dealing growing drug ring to create some sort of surreal illusion as a distraction for news listerners.
My point being just because you dont sell does not necessily make you less of a target to a dedicated group of individuals who are brainwashed into believing any amount of cannabis is as bad as sending $1 to support Al Qaeda. They love the big raids and the headlines it gives them, and youre right, they wont bother with raiding one house to bust someone with 3 plants.
But from the example I gave here, this is how they deal with the small growers, group them up and charge them for being a drug ring.