[morzh]

I always plug my radio in the isolation xfmr and my generator in the wall outlet. This way they are de-coupled and should you touch two with two hands (I still try to avoid that) nothing bad will happen. If they are both plugged in the transformer, it is the same as if they both plugged in the wall outlet with the sole difference of you now not being able to complete the circuit to Earth but still able to complete it between the radio and the generator should the radio polarity be such that you touch it's hot and the generator's chassis.
Worse yet, if in the case of the wall outlet, if it were GFI, the GFI would save you, when both plugged after the transformer, the GFI will not act.