Due to property being in Ephia's Well and the insane likelihood it is of spilling over a DM should be required to do PVP in property of Ephia's Well seems like a no a brainer to me.
this is actually already the case!
A DM is required to PvP in these areas.
I will outline a few rules RE: the incident that sparked this thread.
Indirect PvP
Certain nonviolent actions qualify as initiating PvP and require the presence of a DM to use in populated areas, including:
i. Using the rogue's Cut Purse tool in an attempt to pickpocket another PC;
ii. Throwing rotten fruit or otherwise engaging in extreme provocations.
iii. Before engaging in such actions, you should set your status to be hostile toward anyone you reasonably expect to offend.
Faction Doors
Characters may not utilize faction HQs or plot-locked (non-bashable/pickable) doors for the purposes of PvP unless they have permission from a DM. This includes law-enforcement PCs bringing a character into their faction for "questioning" with an intention to make a more significant arrest.
Self-Defense
If your character is attacked, or if someone else is engaging in PvP, you may always respond IC with no confirmation from a DM.