The real problem with the crime of smuggling of illegal aliens and the harsh penalties comes from the Patriot Act. The Department of Defense and Homeland Security (and frankly every US citizen) are sensitive to potential terrorist entering this country secretly.
The sentencing guidelines are such that the prosecution will tell the defendent what potentially lies ahead if they go to trial. We know of inmates we did time with for this very crime and plead guilty - they got five years. If you are committing a crime, the severity doesn't increase or decrease based upon unknown elements like prior criminal history of others involved. For the reasons stated above, this is considered a very serious crime.
Accepted Answer Date Created: August 17,2015