You can obey every rule of the road.....and they will still pull you over. Last year we were coming through Raton NM. We were driving an 08 Cadillac, both in our mid 50's with greying hair. I was running 72 on the GPS in a 75....on I-25. He was going South and I was going North, when he gave me that look. He spun around and pulled us over for doing 90. I pointed to my GPS and he came back with the arguement that HIS radar gun was calibrated daily and wanted to know when my GPS was last calibrated? He was looking for any kind of arguement to escalate the situation. I yes sir'd him to death and took the ticket ($91.00 for doing 90 in a 75.) He kept asking me if I would like to take it to court. I've been there and done that. Who's the judge going to believe? His peace officer or some out of stater. Even if they do drop the charges, they still get you with court costs and the gas and time it took to get there.
The point is......they can stop you just because......and there ain't nothing you can do about it. If you don't want to get busted for weed.....don't take it with you. But if they really want to bust you....they can. It's your word against theirs if the weed they just some how found in your car....was planted or something they actually found. If you look the part.....it doesn't take much for them to sell it to the judge. If you can, try and video the whole confrontation.