I can't help but feel that the current implementation is a placeholder to simulate danger where there is none. The big disconnect here is you're presented with a game that attempts realism but makes a huge concession in favor of 'exciting' game play. From a logical perspective, does the current approach to NPC piracy make sense at all? Not really. The simple fact is that the NPCs do not exhibit any behavior that simulates rational thought. If you were a pirate, would you be hanging out 100LY away from civilized space? No. Would you be attempting an interdiction in secure system? No. You'd be hanging out in anarchy systems along established trade routes in colonized space with about ten of your buddies. There is no consideration of risk vs. reward when designing NPC encounters and it's jarring. To be attacked more than one jump away beyond the civilized space is beyond absurd. The explanations provided (marooned explorer, prospectors defending a new claim, etc) are so statistically miniscule that they are laughable. That's why I can't help but think the developers have taken this all into consideration and what we have is just a placeholder.
There are so many other environmental dangers and miscalculations that could be fabricated for exploring to make it exhilarating, and I hope this kind of thinking makes it way into the future of ED. Even trading within secure systems could have so many other risks other than piracy. I hope for the sake of realism and more importantly gameplay variety other ideas are taken into consideration and ultimately implemented.