@Stitch
Totally agree with your comments regarding the technical/mechanical limitations, and this suggestion doesn't address any of them.
However, it does, I think, make it easier for the 'victim' to understand whether they're up against a ganker or a PvP pirate - which I think would reduce the tendency to combat log immediately upon interdiction.
The key thing, I think, about this suggestion is that it would allow the pirate to gain cargo even if the target combat logs. Ship loss after a real network disconnect (not combat log) is something that FDev want to avoid, but losing (say) 4t of cargo is, I believe, on a completely different scale and does not constitute a huge punishment for something that isn't the player's fault.
It's quite an artificial way of handling it - I'd rather not see piracy
deliberately boil down to "press button, target clogs, 4T of cargo appears, move on".
As above, piracy is the "profession" most boiling with potential for dynamic PvP engagements; the pirate should be able to choose how he approaches his target, be it through sheer social engineering, skilled module disabling etc., and see choice and consequence take effect. Successful negotiation with the target, everyone walks away unharmed; trader rejects demands, pirate aims to shoot out his thrusters and then cargo hatch, and cops will arrive to apprehend the pirate - but the trader may be damaged and ultimately lose
considerably more cargo. There are more methods available but choice and consequence absolutely need to be the driving force in this game.
Ultimately if FD were even half bothered about piracy they would reinforce that combat logging is a no-no, pure and simple. It's not the pirate's responsibility to have the tools to ensure the target doesn't cheat to escape. And if this were reinforced we might be reminded that choice and consequence should exist as more than punishing murderers and pirates; it should affect every player in the game, as the very lifeblood of "blaze your own trail". Don't want to get pirated? Build a trader with more than the minimum shields and no armour. Want to know if you're about to be pirated or murdered? Take the five seconds to check the sub targets panel, which should reveal quickly whether the assailant has piracy based modules.
Don't get me wrong, I am not against tools for piracy; it would just be more effective to smooth out base mechanics first, be natural, and
not be an attempt to make piracy harmless. Hatch breakers through shields already tried that

And on a side note, without wanting to start the argument about it, as long as there is no incentive for players to trade in Open...well, I don't really need to finish that, do I? Let's not blame murderers and poor piracy attempts for the utter ambiguousness of ED as a "multiplayer" game.
So did we or did we not establish that the whole point of "piracy" versus "murder" is the difference between "profit" or not? Now I'm sort of confused, because the arguments I most frequently hear from pirates is "we're not murderers" (and conversely "don't equate us with such"). With this, I can only deduce, that perhaps before FD can expand "Piracy" as a profession, the community needs to decide what the actual definition of it is?
Well it's someone wot stole cargo, innit? The motivation for that,
at present, is 110% for enjoyment over profit; I wouldn't be surprised if PvP piracy were the lowest paying activity in the game. Back when engineers required cargo there was a second less frequent motive, being one could pirate engineering modules, but even that hidden little nugget of content got blitzed - and now we're back to cargo being a sole money printing tool.
Ofc don't get me wrong, I would kiss an effigy of Braben if piracy/crime in general became the high risk, high reward beast it deserves to be.
As a side note pirates are quick to dismiss links with murder for multiple reasons, but tbh it's not their issue to fix if some people break down at the notion of a PvP player that doesn't spend every waking minute seal clubbing. Almost any discussion here that relates to crime or PvP inevitably tends towards "punish murderers!" as the thread continues, and many pirates are bored of that being the only discussion point, and of their profession being mangled to hamper murder (murder ironically being the least affected) - not to mention groups like the Code rely on a reputation of asking nicely before getting mean.