You've all given great replies ... so if my idea isn't an answer to griefing, what would you all suggest?
Frontier are pretty clear that interdicting, and/or shooting and/or killing a (locally)-Clean ship, is not only not against "the rules" but is in many circumstances at least somewhat encouraged:
- bounty KWSed from another jurisdiction
- piracy (especially if you're not very good at
carefully disabling drives)
- PowerPlay
- assassination missions (players don't yet end up as targets for this, but they were talking right at the start about two players being able to take roles in the same mission, and don't seem to have given up on doing that someday)
- combat zones
- BGS effects
- Anarchy systems
- that guy who flies right in front of you in a RES while you're shooting a pirate
- first-strike against potential aggressors while running escort
- etc. etc.
That being the case, really harsh penalties for getting a murder bounty (enough people with itchy RES trigger fingers complain about the existing trivial one) are unlikely to be imposed. Financial penalties are unlikely to do much good, given how fast the latest earner of the month gets people credits if they wish to use it.
Next, ship build has a massive effect on combat strength - a pure combat ship gains as a minimum probably 3 internals and 1 utility on a pirate, 5 internals on an explorer, 3 or more on a trader, and 4 plus weapons on most miners. The attacker, of course, often has the ability to pick targets to avoid fair fights, if they wish. No plausible amount of NPCs can take on a pure combat ship once engineered.
Finally, determination of the aggressor is in many cases not straightforward - the existing mechanisms are certainly exploitable, but on the other hand, in the real world, thousands of hours of lawyers time are spent determining fault in case of collisions ... no-one should expect some automated rules to make a correct instant decision every time.
My preferred long-term "solution" would be to significantly increase the danger - and likelihood of death - from NPCs, by making their attacks more frequent and skilled, and by reducing the maximum toughness of any one ship. At the same time, reduce the consequences of death for non-combat players through means such as cargo insurance, some means of exploration "checkpointing", etc. so that deaths more than once every few months can be a normal part of the game rather than something which risks wiping out all progress. Once the NPCs - as in the previous games in the series - are killing everyone, then a player occasionally doing the same is hardly a problem. Everyone can then go around in Open/Group/Solo as their current desire for sociability and high-res screenshots suits.
... but for a lot of players it's not "being killed by a player" that's the problem, it's "being killed", so that's not going to help.
... and it'd require such a massive rewrite of so many game mechanics I think it can't be reached from here anyway.
... so in practice, I think the "solution" is "stay away from obvious hotspots in Open if you don't want the risk"