You're saying that it is totally safe to turn on my QCX40 & practice, without an aerial or dummy load, just as long as I don't transmit?Mark,
Totally safe if you do not make a mistake and transmit!
The reason a dummy load is recommended is that it has happened in the past. Since then the firmware has been modified to make it less likely, but not impossible.
Also it has been said that alignment sometimes works better if a load is present although that is not so important.
73 Alan G4ZFQ