Is that actually common? Don't know about the US but haven't seen very much of that in the rest of the world.
Yeah, totally common (Brazil)
Drugs possession is criminal in many places throughout the world. Police departments throughout the world have some kind of quotas. If a quarter is ending and am officer is five cases away from maxing out his bonus, what's to stop him from finding some potheads and cashing in?
In the US, it basically depends on how poor and/or black you are. No joke.