Continuing here to not derail that other thread further:
That reminds me, will a vengeful relationship be reversible/harder to acquire in .7? If a negative relationship to major factions becomes commonplace it would be a hassle to get permanently stuck there (easily).
No on both counts. It's not something you can acquire accidentally or, for that matter, easily - you'd have to pursue retreating enemy ships while already deep into "hostile".
Well, there isn't any kind of warning, so, yes, it happens accidentally. For once if you don't know about the consequences of pursuit - it is not communicated anywhere in the game IIRC - but also when you get distracted by a some objective you have. For example, if the flagship of a named bounty fleet gets damaged and retreats, or if you attacked a fleet to board a specific ship and it retreats.
It also works the other way around, when I'm not
absolutely positive that my relation to a faction is still OKish I don't dare to pursuit them because they
might permanently hate me.
In any case, some more transparency would be nice here.