That is pretty dangerous if someone accidently turns one amp on while the other is also on. It will happen one day.
I have a preamp that outputs to 2 amps which are connected to 2 systems, a 2-channel and a headphone amp. I also make sure only one amp is on at anytime, however, I will not have a blowup if I accidently have both turned on. That has happened a few times.