Arthur, you know half of the answers already, don't let the poor saps who want you not to pirate them by any means, get you doubting them.
If it's not nailed down you can demand it, if you're feeling mean you can demand they pay for their lives. You fly a Rogue most often, feel free to mug them if they are completely stripped bare of cargo, ammo, bots and bats. We're not supposed to be nice.
If you wiped the trader out and he comes barreling out of the trade lane shooting, he's just re-engaged. Traders taking the liberty of walking back through a system before 4 hours had better be doing so quietly and without fuss. Once you're dead you don't get to open fire first, simple as that. That applies to anyone and everyone.
Oh and for the rest of you, the Rogues don't offer day passes. If you're daft enough to keep plying the same route we're smart enough to keep robbing you.
Saint Del is considered a holy healer of diseases of children, but also as a protector of cattle.