Section 3303 - Nonliability for enforcement of lawful tariffs and rates(a) Public utilities.--No public utility, nor any officer, agent or employee thereof, shall be liable for any penalty or forfeiture, or be subject to any prosecution, on account of demanding, collecting, or receiving any rate for any service, or for enforcing any regulation, or practice when such rate, regulation, or practice is contained in a tariff properly filed with the commission, and posted or published as herein provided, and is applicable by the terms thereof at the time to such service although such rate, regulation, method or practice may by found by the commission to be unjust or unreasonable.(b) Contract carrier by motor vehicle.--No contract carrier by motor vehicle, nor any officer, agent or employee thereof, shall be liable for any penalty or forfeiture, or be subject to any prosecution on account of demanding, collecting or receiving any minimum rate prescribed by the commission under the provisions of this part. 1978, July 1, P.L. 598, No. 116, § 1, effective in 60 days.