Most mobile phones are smuggled in by prison staff, who often do not have to go through security as rigorously as visitors. Security of staff is often less intense because this would be time-consuming on the part of the staff, unionized prison employees are paid for this time, and it would thus increase the overall cost of operations,also, prison staff are often reluctant to diligently search their own co-workers to avoid agitating their colleagues and damaging workplace morale.
More rarely, mobile phones are smuggled in by visitors, who must undergo tougher security checks, by inmates who are granted temporary leaves of absence, or by outsiders who establish contact with inmates alongside the prison fence and/or deliver them using drones.
Once inside prison walls, the cell phone jammer end up in the hands of inmates who purchase them with cash, which is also contraband in most prisons. Black market prices vary by prison, and can be up to US$1000.
Not all inmates use mobile phones for harmful purposes. Many inmates use them to hold innocuous conversations with family and friends. In South Carolina in September 2012, an inmate using an illegal mobile phone jammer alerted authorities about , leading to that officer's rescue.
