OP, you are quite right of course -- Player Made Faction (PMF) undermining, with no direct way to combat it, sucks for sure.
The issue is the result of FDev's lack of foresight as the problem was introduced as soon as they added PMFs with no ability to join them or control them. (FWIW, I was never against the idea of separate Solo\PG\Open modes before the introduction of PMFs [heck, I even thought they were a good idea at the time] but after PMFs were introduced in their current state I became opposed to them.)
But your suggestion is not complete.
The legion of FDev Defence Force white knights will quickly tell you why you are wrong. They fall back on the original Kickstarter plan as the ultimate justification for their position while making the assumption that nothing else in the game would have to change for FDev to adequately address the underlying issue of PMF undermining that you raise in your OP.
The fact that this issue comes up over and over again is testament to the fact that the original design of the game in this regard is
flawed. FDev, of course, knows this but won't admit it and no doubt feels its hands are tied.
So far FDev has not added anything to make this situation any better. Worse, they adopt the "gun maker's" argument for related issues like PvP --
"we only make the guns [you can hide in Solo\PG if you don't like PvP], we don't make people use them in any particular way". Lame; way to wash your hands of the problem FDev.
Working the BGS is (at the moment), unfortunately, the best way to combat PMF undermining. But for many, grinding the BGS is extremely boring and unsatisfying and takes away from other things they would rather be doing.
How to fix the situation? Off the top of my head the following things would likely need to change:
- Cross-play should be a thing like in most modern games
- Better instancing than this P-2-P stuff we have
- Everyone plays in the same mode (i.e., Open Only or something similar... but I know, I know... let's not go there right now)
- The ability to join our PMFs (the best we can do now is to create a squadron name that is similar to our PMF's name, lame...)
- The ability to declare war\peace\truce with any number of other PMFs
- Going to war with another PMF and attacking their ships should not make us criminals just like fighting in a CZ does not makes us criminals
- Change blocking so that it cannot be abused (e.g., blocking your enemy PMF's members so that you can undermine without opposition)
- Let us more easily see PMF territories in the GalMap
- Weapons balancing & shield stacking (optional)
- Whatever else that I am not thinking of
Being able to go to war with another PMF is key because even if you don't know for certain if one of the others PMF's commanders is trying to undermine your PMF
at this very moment, the kill-on-sight nature of war can lead to in-game diplomacy that can be used to resolve the PMF undermining (which I think would be AWESOME emergent game-play BTW).
Something like this would be welcomed. Just look at Inara how so many squadrons create "alliances" or "coalitions" with each other. Such agreements don't exist as a mechanic in-game and have very little in-game effects. About the only effect they have is a sort of promise not to attack each other's squadron mates and maybe help each other with the boring grind of the BGS to combat PMF undermining. But of course hiding in Solo\PG easily undermines such agreements as does the rampant abuse of the ill-conceived "block" functionality (i.e., people routinely block anyone for any reason whatsoever and even block people whose squadron is dedicated to trying to protect traders, protect AX commanders, etc. so that they can more easily "gank" or pirate (a legitimate game mechanic BTW) others without interference, etc).
Here's to hoping that this becomes a thing in New Era.