There was likely no searches because the prison officials tacitly are involved with the smuggling and need to not search anyone to make it look like a uniform p

There was likely no searches because the prison officials tacitly are involved with the smuggling and need to not search anyone to make it look like a uniform policy rather than an exceptional policy for the smugglers. Had you actually brought materials to the prisoners, whoever was doing the actual smuggling would have found out through the grapevine and you would have been promptly arrested. My humble conjecture.