I posted this before:
My wife and I are religiously married (Jewish). The state has no business regarding my marital status. Most of my wife family immigrated to Israel from the Ukraine. According the her it is common in Israel to marry without civil license.
A couple of caveats. We were both in our late 30s when we married (my first her second) and we did not plan to have children. My wife already had two great children, the youngest was my best man.
What if you are a 35 year Green Beret who is Muslim and has 4 women that you want to marry, does the government need to decide if those marriages are valid for housing and rations and as dependents when you are stationed and housed in obscure places on the planet, or do they just depend on the Mosque to define it?