Namcha
The idea is more to put consequences on little acts like teaming with enemies on daily things (exchange, hunting...)
Not something that will drop fame to the abyss. But losing max fame could be already a serious matter. (could be easily retrieved with missions, but, if every days....)
I guess there are 2 ways:
Consequences or Restriction. But both do the same: Factions will work more together and alliances wont work as it is. If we wanna this type of gameplay, here we go ;-)
So lets go deeper in practically manner:
Actual there are two layers: Factional PVP and PVE. (Other PVP like duels or OP-Fight wont have any effect.
Loosing or gaining Fame by every kill is not a big deal and wont encourage players to be more tagged than it is.
There should be a motivator for being PVP tagged. Thats what we are talking about in this actual system. PVP just for fun can be also done in duels or in the matis arena i.e.
So earning something except PVP-Points should be implemented that is worthy for everyday habits. Dappers is a good thing to steal/earn (depends on your RP).
Another idea is: To steal dappers, you need to make the enemy weak lets say about 10%-25% of you HP must stay. Then you have to stun or sleep the char. ONLY then you can loot dappers, factions-points etc. or something else, what makes it difficult to loot, but still possible.
There should be also a BIG WARNING, that it can be stolen some Dappers from you if you activate the tag.
When it comes to PVE (hunting, leveling) , there could be also a fame mechanic to gain loose fame. (addition to be clear: that happens only if you are tagged)
Lets say a Mara and a Karavan are hunting. Mara will loose his own fame, but gain Fame for Karavan and the Karavan will loose his Karavan fame and gain Mara fame. But it should be still low by every kill. Lets say 0,06 by every kill. That should only work if both chars are aligned (my opinion).
Another Situation: Ranger and Mara are hunting. Ranger loose 0,01 on Fyros, Matis, Tryker, Zorai, Kami and Karavan, but gain 0,06 in Mara fame. Mara loose 0,06 fame on Mara, but gain 0,01 on Fyros, Matis, Tryker, Zorai, Kami and Karavan.
Neutrals with no alignment should be an exception. Or a fame restriction: You cant loose any fame if you are between -50/+50 Fame.
I think that is acceptable.