to elaborate the FR5 especially - there are 2 versions of it that could technically be applied
there is the - 0.9 version - that sets a player and/or group (tag) hostile - but they can by bribe or killing enemies of that same faction - make up for it - a natural rep up from being hostile. - that one could be faction controlled without much detrimental misuse.
- 1.0 version - that sets the player and/or group (tag) hostile - with NO way to rep up without admin help. the reputation is locked hostile, no matter what (like nomads are hostile to others, even if you kill countless of their enemies)
that one could be admin controlled or allowed to be requested.
additionally - there could also be a +0.9 verion and a +1.0 version to make real friends that are even able to fire a train CD into a furball angering only the enemies but not the friends.
adjustments would need to be made for factions that have no own direct reputation mod ( up to a point like zoners - but you can rep up with them by assisting GMG still )