Every person who, without permission of the peace officer or corrections officer in charge of any vehicle, bus, van or automobile used for the transportation of prisoners, delivers a written communication to any prisoner or person detained therein, or being escorted to or from that vehicle, or takes from or gives to the prisoner any item, is guilty of a misdemeanor.
Source:
Section 4570.1, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=PEN§ionNum=4570.1..