—“You speak from time to time of hanging malcontents, and bigamy in England was originally a capital crime. Could I be hung for bigamy?”—

I would love to say yes just for fun. But bigamy is not a violation of natural law, but of public contract for the production of a commons.

—“But if consenting adults agree to a different contract?”—

If consenting adults agree to a conspiracy you mean? They simply both violate the terms of the (explicit) public contract.  By explicit, I mean written in strictly constructed natural law. (Propertarianism)

—“Bottom line, though, is no violation of natural law, no hanging, right?”—

Right. They can kick you outta Dodge. And they might hang you for not leaving Dodge. But in general, a contract violation is a matter of restitution. Since departure is sufficient restitution – that’s pretty much all that matters.

People can make normative public contracts all they want that limit consumption. They just cannot make normative or public contracts that engage in parasitism.

Limiting consumption is the purpose of commons – including the commons of property rights. (which may not be obvious).