They don't really need masquuerading, as SIM is programmed to access Vodacom towers. When SIM is proceeding with handover, it is allowed to do by the tower, but such tower is not generating any traffic, as device is in 3G mode. When it happens, modem is stuck to this tower, as is unable to renegotiate connection and the subsequent modem boot-up is affected as well, as modem remember the last succesful connection details and attempts connect to the same tower. This tower refuses to register in 3G mode, while it allowed to handover in the same mode. Such "software glitch" can cause havoc to the original network. It is like the virus infecting DNA.
There are numerous threads related to it "Stuck on... unable to". So I made my educated guess sometime ago, and now AKC says about the same things.