Most certainly not. Perhaps the emperor whose word was law, but a simple noble could not go out and kill servants or people invited by their children onto their land.
No one would work for them if they could simply be killed. Slave owners weren't even allowed to kill their slaves during the Roman Empire or American Slavery.
Of course, that's the theory behind the law; the practice is often different. But so it is today and power persons have a habit of escaping the law when what they did was a crime.