Tribes do not have a built-in governance model. Hive-Engine tribes and tokens are fully centralized -- controlled by a single Hive account.
They can choose to emulate PoS/DPoS, but that is really only a facade. Ultimately it comes down to the whims of whomever has access to the Private Keys of the issuing account.
When you ask for governance , Democracy is the most accepted form of governance and tribe should have the same but as we can make multiple accounts so these "fake votes" make challenge to run a democratic system.
We need to find a way between POS and "democratic" vote system for governance.
I am not a huge fan of purely 'democratic' governance. Democracy just means the majority faction can oppress all minority factions and feel 'justified' in doing so.
The beauty about Layer 2 tribes is that you can readily create your own tribe with its own governance system. I am currently fleshing out a new governance 'system' (with the help of a few others) that we are tentatively calling "Proof of Stewardship". We will share more about it when we have more to share.