I would like to add, that I almost NEVER get interdicted by Elites and Deadlies despite being "Dangerous" rank. Am I being punished because I like to fly small combat ships?
After this comment, I decided to do a quick test as I wanted to sell all my old pre-2.1 Sidewinder bookmarks anyway.
I took an un-armed/D-Rated sidewinder on a 23 jump tour and did not get a single interdiction message/attempt.
I then moved to my well armed A-spec Asp Explorer and took another 28 jumps. Again, not a single interdiction attempt.
In both cases I had no cargo as well as being in a non-combat ship (IMO).
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When I'm flying my Cutter I'll be lucky if I make 5 jumps without at least one interdiction from a Deadly/Elite Anaconda or FDL.
I get scanned every time I enter a pristine metallic in my mining configuration but I suspect this is scripted as its usually a pirate who leaves when he sees I have nothing but limpets or a Security ship (Again, no issue). I was not paying attention on the random ones, but I often have cargo on board.
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More testing required, but I'm now seriously suspecting the random non-mission etc related interdictions are based on what you are flying/carrying and not your rank at all. Maybe the game only sees my Cutter as a huge battleship when I, and many others, see it as a huge cargo/mining ship.