its most certainly not the answer.
even aside from the fact that the OP said govt should not recognize marriage in ANY way, the response still fails to answer the other points i raised.
if every chucky cheese can perform a valid marriage and the govt has to recognize them all, a man can have 1700 wives. who is next of kin? who gets custody? who pulls the plug when the spouse is a vegetable? marriage isn't just a contract its a very special kind of contract. if marriage become a null institution and it fell to contracts in the free market, it would take years of contract case law and court precedent to sort out the mess that would result from conflicting contracts regarding property inheritance, custody, etc. whole institutions regulating precedence in multiple marriage cases would have to develop. property would have to be held in escrow for years while multiple wives and husbands battle it out, with dna tests on the poor kids involved to determine actual parentage.
on a deeper level, if every contract is valid and should be enforced by the government, than we enter the dark area of questions about whether individuals should be allowed to sell themselves into slavery, sell their organs for money to buy crack, submit to marriage conditions similar to slavery when in the emotional grip of infatuation to a man or woman, submit to loan or debt contracts that allow physical abuse or taking possession of the borrower's person as collateral, and 101 other fun possible contracts that could happen in an entirely free contract market.
should the govt enforce them all simply because the parties agreed to them?