I have played open for a long time, and had never been interdicted by a fellow Cmdr. Then I joined a faction and was not only interdicted, but popped, after less than five minutes from the moment I pledged. At first, I was somewhat disheartened by this. As you say, had it been pre-pledge, I would have been seriously hacked off. But now, having dusted myself down (insurance & cargo loss cost me about 15% of my cash surplus) I accepted, like you, that this was the reality of PP. I had considered this, and thought long and hard about pledging, before diving in. However, the first time it happened was still a big shock... but, it is fair. I can't argue with that.
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The thing PP has brought me, therefore, is a real tinge of danger. Jumping into a system now means a proper scan of what Cmdr's are around. A constant vigil, between arrival point and destination port, of the radar. Exchange of information with other friendly Cmdrs about enemy combatants one has seen around in various systems. I have yet to fall foul of interdiction again.
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For now, I enjoy this. Maybe I will tire of it if I get blown to smithereens over and over. I'm sure it will make me a better fight or flight player in time. If I do tire of it, I have my 'old life' to go back to and many systems to do my own business in.
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All in all, I think it is at least worth giving it a fair crack if you have some spare crédits (note insurance is reduced in some factions!) and can take a few knocks. I don't think it is hard to take a two hour break, say, from faction activity, to concentrate on making the money lost back, and using un-factioned space to do so, should be fairly safe to do so. OP is probably right to try in a cheaper ship first, at least to get the lay of the land. Wish I had thought of that!