I'm sure they'd give you a ton of weak justifications. You're a cop. They want you to take pity on their pitiful story so, I dunno, maybe the charge isn't as severe.
I'm not gonna toot my own horn. But I never smoke outside the privacy of a residence. I also don't buy in non secure locations. So there's something to be said for not getting caught. Keeping things in house is a good strategy. But essentially what you arrested him over is stupidity, not marijuana use.
That's kind of the lunacy of the police. They only arrest those dumb, or poor enough not to cover their tracks.
The drug didn't lead them to a life of crime. If you're stably employed you can purchase weed fairly regularly. Your drug dealers don't bring guns to your house. You're a customer, they don't want to scare you off! He's usually some dreadlocked white dude anyways who likes Bob Marley and lives on his bike. If it causes you to get fired, it isn't the weed. The laziness is a personal issue, mostly from television depictions. Like I say, two hours in the gym today. Gyms are stoner havens btw.
It's not the drugs that cause neighborhoods to be violent, it's the lack of money, real wealth and perceived pestering by the "outside" world.
Good points....sort of. You assume that I am a street level cop or possibly detective on some level, but I have held many positions in law enforcement and spoken to many many individuals after they have already been arrested and convicted. Therefore, they had no reason to lie (no benefit) or place all of the blame on marijuana (or any other factor). These conversations are fairly candid and in some/most cases, surprisingly honest. I have spoken to many people who were released from prison who talked about weed in this same manner. Again, no real benefit to lying or not taking responsibility at this point. Being in law enforcement, I do realize that some people lie for other reasons, but again, I have done this a lot over 10 years, so I am playing the percentages.
That said, what some have said (including myself) is that weed typically negatively affects those that are already weak or lazy. I completely agree and yes, there are really successful people out there that smoke weed, some of them regularly.
I had multiple extended conversations with a female nurse that was addicted to prescription drugs. She comes from a very wealthy, successful family. We spoke about her beginnings with these drugs, how it made her feel, why she continued to do it, etc etc etc. In other words, I asked her about almost every aspect of her life and how her addiction affected it. She spoke about herself in a way that I had never heard before. She talked about how her brain (and every person prone to addiction) works differently than "normal" people's brains. The conversation was strange, revealing and informative.
So, whats the point of this story? She didnt know that she had an addictive personality until she first tried drugs (not weed, but the point is the same). So, if what she said is true (a lot of it was based on actual research), it is a risk for some people to even sample ANY drug, as they could become addicted.
So, again, it always boils down to personal choices. If a person decides to use drugs and they become the next Steve Jobs, then good for them. If they happen to get caught in possession of them and do jail time or get addicted, then that would be terrible.
So, as some people have said, using marijuana is potentially risky behavior....I dont think that can be argued. And yes, I know that even driving a car COULD be risky, but that isnt really comparable to choosing to use drugs (many people HAVE to drive to go to work, getting caught just driving wouldnt lead to an arrest, etc). Even what you said about using drugs at home and avoiding certain areas and such diminishes the risk factor (again, that is a smarter choice on your part).
I apologize for taking this off topic a bit, but did want to give my perspective about some of the comments.
Back to the mom, I dont know if her punishment choice was smart or not. It may work well, it may completely backfire. Only time will tell.
There are these things called condoms. And this other thing called birth-control. If you have just a bit of common sense and are careful with who you have sex with and how, it's not only extremely fun, but very safe. 
