An important issue with regards to the interdiction of narcotics at the U.S. Border is how the U.S. Attorney decides to "prosecute" on various case scenarios. Remember these are people that basically have no "street" narcotics experience and sit in a legal office most of the day. They really don't know or care to know what the narcotics agents go through or how it really is on the street level. They are paper pushers and follow policy. They also make deals and write off a good narcotics load just because they don't feel like it. After all the hard work that you went to catching the bad guys.
I most "normal" smuggling cases, a good Customs Inspector/Agent will make a determination prior to having to call the U.S. Attorney's Office for "permission" to arrest and follow through on a prosecution case. This is to make sure they have a very good case and all the details are enough to seal an indictment or arrest.
There are certain "guidelines that we must follow to determine culpability or responsibility. Therefore, you might have a lone male/female drive driving a car that doesn't belong to him/her. They have only one key, no proof of ownership, temporary status to the U.S., just going to drop off the car, etc.........The list is endless of the stories I've heard as well as other Customs employees have. We've heard them all. Our job is to ascertain which is the truth. Most will not even have any identification if they are chancing driving a "load" across the border.
If you can ascertain that the driver "owns" the car, instead of borrowing it, then you can show reasonable knowledge that the driver should know about his/her car and it's contents.(like what's in the trunk, glovebox,under the hood, etc...) You can easily prove to a jury an open and shut case.
Some smugglers are not so smart and break under the pressure of smuggling. They are even being told that Customs can not tell if they are lying. I know different. You have to look into there eyes and you can tell. Hopefully with other behavioral analysis techniques.
Anyway, you've got a "border crosser" who lives out of the area an is traveling to "L.A." or just across the border, depending on which border town you cross. They don't fit the car or can't explain all the regular and normal things that are "missing" from the particular scenario. I saw on where the car was a brand new Ford and there was no luggage or usual items for a trip. The driver and passenger were from Sinaloa and driving a new California licensed vehicle. They were both "dressed to kill"(well dressed) and going to L.A/ from Calexico. A determined young Customs Inspector kept after the search until "He" was satisfied instead of the Supervisor.
After a good interview and subsequent search, the Heroin load of over 5 lbs. was discovered in a Mexican chocolate cocoa can welded to the inside of the new gas tank. There was a silicon sealed plate on the top of the gas tank which was not visible unless you dropped the gas tank. Persistence paid off in spite of what the Supervisors wanted to do. I have even seen where some Latin Supervisors will even risk losing or not supporting a narcotics search by certain Customs Inspector not of the same culture. They would rather see one of their "own" get a narcotics load or credit for doing a good job instead of the "other guys". (I have personally seen this happen to both black and white Customs Inspectors alike)
Anyway, the past levels of narcotics which determined if there was a prosecution or not was determined by the U.S. Attorney's Office. Once it was over 300 lbs and later dropped to 250lbs of tolerance. If you had less than that, you were returned to Mexico after being administratively processed if you were over 18 years of age and a foreign national. I saw where a juvenile American Citizen was released to Mexico after smuggling over 200 pounds of Marijuana. He lived in Mexico too!
If you over 18 years of age and an American Citizen or U.S. Resident you will probably get jail. If not, you might get released unless you become"cooperative" with the Agents at interview time.
I guess the federal government and the U.S.Attorney have decided to spend tax payers money on people who live here rather than all the illegal aliens that infiltrate our country every hour.
In other case scenarios, the violator is a Mexican official and is given "special" treatment so we can use that as a favor for later. You and I may never benefit from such a "por favor" but that is what happens. If you or I got caught in Mexico with anything, forget everybody. They will not help you even if you are being "set up". It is not uncommon to "set up" certain people while they are on a visit. (That's why I used to check my car very well before entering or leaving the country.)
I have seen where snugglers will use "grandma's" car on "wash day" and put narcotics in her car, knowing whe will cross on tuesday every week. They will then duplicate the key or find some other way to obtain the narcotics while it is on the U.S. side.
Just think of all the money the taxpayers are saving by not arresting everyone with over 50 lbs of narcotics.
Yet, in the State of California, anything less than a pound is a misdemeanor. Otherwise it's a year or more in jail, or state prison. It's all at the discretion of the U.S. Attorney. We have to pay for room and board you know.
So unless you can tell a good story, you may be a guest of the People of the United States. Unless of course your an alien with no status here in the U.S. or have legal right to be here. All the criminal aliens know this. They know exactly what to say when they get careless and get caught. Then they just get "deported". The revolving door syndrome. They suddenly speak "no English".
I have seen that scenario happen many times as well.