Been ripped off several times as I'm too trusting a person, usually for small amounts, but not always. Avoid people who are chronically addicted to weed, or to any other drug. I'v learnt that the true addicts can't be trusted, even if they were once your friends.
There has been a rise in robbery in my country, my dealer tells me how a few folk he punts to have had their front door's kicked down by gangs with weapons (golf clubs etc), and its because they have big mouths.
Now I take my 30x loop when buying from a 'new' dude, and make sure I sniff the bag first. I've been sold Vietnamese crap under the pretence of it being proper stinky weed, felt so stupid.