Effective February 2009, the IMC and IRC now require that all outdoor access ports be made tamper resistant.*
*IMC 1101.10 Locking access port caps. "Refrigerant circut access ports located outdoors shall be fitted with locking-type tamper resistant caps."
*IRC M1411.6 Locking access port caps. "Refrigerant circut acccess ports located outdoors shall be fitted with locking-type tamper resistant caps."