welp, a few years ago here in Tennessee, there was a big tax hike on cigarettes. so high, that it drove people to the point of driving up to Bowling Green and even as far as Paducah in search of cheaper prices on carton's of cigarettes. They would buy several cartons and go back to Tennessee. TN Dept of Revenue soon caught on that this was going on (not sure how, probably someone ratting on people), and they started staking out these people and gas stations across the border. They'd go monitor gas stations and what not and have people in the stores as "customers", who would radio outside to the unit, that unit was usually in a completely unmarked and plain vehicle with normal TN tags on it, and that would guy would call ahead on a cell phone to a trooper sitting on the TN border side with description of the person, plate and tag #, the trooper would then pull over the unsuspecting offender, and arresting them! in some cases, seizing their freaking cars!
http://www.knoxnews.com/news/2007/se...-begins-today/
Colorado can hire "civilian informants" to go follow people across the border and report back what they are doing. Since a "civilian" reporting something bypasses and circumvents many search and seizure laws and requirements for a warrant, this could get quite nasty in the future, if these laws are passed and put into effect.