Unless it is a high power output generator, generator with output in the +20 dbm max. or less need no short circuit protection.
As previously mentioned, if generator is considered a test set for a transceiver, like a cellphone, there may be protection from accidentally keying the transmitter with a couple of watts of RF power back into the generator which can damage in output step attenuator (which typically can tolerate a maximum of half a watt of reverse power injection).