Robbing is not PvP as such in my book, it is piracy, the goal isn't to destroy the target but to take something they have that you want, if that is your aim then I can see where you might end up frustrated.this was your words
It sounds like I need their concent to pvp them which regardless of whether if they can or cant defend themselves I will rob them.
That said I read it as your goal was PvP, a challenge, combat.
There are indeed those that attack others but use logging out as way to get around losing things themselves.perhaps you will care about logging when your friend gets killed by one then you hunt him down to have him just log. If they log I take it as a win but they don't lose anything and that's why im never satisfied with that.
And yeah those are incredibly frustrating, but you do effectively win, an even bigger win then blowing them up in my book.
You prove that they clearly are not a combatant and that they clearly are simply out to destroy easy targets and run away from an actual fight.
Now yes, the fact that they do not lose any material in game but cause others to lose such is a problem, but I seriously doubt increasing the timer will do much, but I suppose it is worth a try, scaling it towards defence and such might not be a bad option.
But that being said, my experience with hunting such people in various other games, that gank and aren't out for general combat, is that they will then work to find another way to avoid death, so it doesn't really solve the problem and more just pushes it around.
A more effective solution in my book is upping the in game punishment, and make it so that the state of your target, their strength compared to yours, also means that for example, if someone attacks a target that is significantly weaker then themselves in outfitting, in the view of the pilot federation they would be attacking helpless people, and that deserves another punishment then attacking those that are actively fighting, but if or if not it can be made properly is a tricky thing.
For all its flaws FO76's damage scaling in terms of PvP might be a better solution, your damage is reduced for x time unless they fire back, but hatch breaking and similar that does other things will still work.
Maybe making the cargo bay vulnerable despite this state?