A method of preventing theft of service in a communication system that includes a first wireless communication system and a second wireless communication system that includes a Femtocell access point (FAP) and a network controller that can communicatively couple the FAP to the first wireless communication system. The method creates an authorized session that includes a session identify for a first user equipment (UE). The UE is recognized by the first communication as an authorized UE to use the FAP. The method rejects a request by the FAP to register a second UE when the identity of the second UE does not match any identity in the set of first UE identities. The rejected request includes the session identity of the authorized session and the identity of the second UE. The second UE is not recognized by the first communication system as an authorized UE to use the FAP.