Yeah, but continuing with my analogy - I don't care about what the bad eggs think. I mentioned "poisoning the well" earlier. The well, in this analogy is the good eggs, the co-operative traders.Not everyone is a "bad egg" - just as not every armed ship is flown by a "griefer"
If people have had bad experiences in the past with an interdiction - they will react to that.
Showing them you are not one of those will help them chill out and respond in a way you like, not try to run / HW etc...
All your doing by killing is reinforcing what they expected to start with. Letting the odd one or two escape will put them at ease and perhaps have them play along next time.
I'm not going to let a "bad egg", a non co-operative trader, go free on the slim, off chance that he *might* turn co-operative in the future. He's not part of the well, so I don't care about destroying him.