A friend of mine got charged for possession(a joint) in Bermuda in the 90's... No big deal...
10 years later his flying from Spain to Mexico with a connecting flight in Miami.
They threw him in jail for 2 days, and then sent him BACK to Spain.
It's weird because Bermuda isn't a part of the US, yet this happened. On top of that, he was handcuffed the entire flight back to Spain and the captain had to carry the keys. When he got off the plane they asked him what he did, the police in Spain just laughed and asked if he'd like a direct flight to Mexico.
So they definitely got the dirt on those systems.