Yeah man, if the flight is operated Part 135 the pilots and other crewmembers ARE not responsible for anything a passenger brings on board that is illegal. Part 91, the pilots and other crewmembers CAN be held responsible.
It wasn't pot or another drug but.........
Years ago we were flying people out of the Bahamas due to an approaching Hurricane. One of the passengers got on with just a duffle bag. When we were going through customs at PBI the guy left this duffle bag on the luggage cart as everyone went through to get checked. The customs guy asked everyone, "who's bag is this on the cart". At first nobody said anything, so he asked again and then started to walk over to it. Then this guy said, "oh, thats mine." It had $410,000 in cash inside. They made us (crew) wait just until they counted it all and then said, "you guys can go, have a nice day." All they asked from us was to sign a paper saying we had no idea it was on board. Later on a couple months down the raod I asked the customs guy whatever happened with that guy, he said he turned out to be a known drug trafficker and the money was siezed. Don't know what happened to the guy though. Part 135, nothing can happen to the crew for illegal things being brought on by paying customers.