I think I'd draw a line somewhere between NRE and alcohol, as far as alcohol impairing consent, and NRE simply making you silly, but I'm not sure exactly why.
Perhaps it's the simple fact that our brain chemistry is ALWAYS under the influence of various waves of chemicals and temporary emotions. If we decide that we can't possibly consent to anything while we are *feeling* something, then we will never really be able to consent, period.
I might step back here and say--- I'm not sure I place as much value on consent as you do. That is, consent is vital when it comes to determining what I may do with your body, as a nonconsensual offensive touch is battery, and properly so. But when it comes to polyamory?
Just because you consent to engage in a relationship doesn't mean I won't have opinions about that relationship, or be judgmental about it. Just because you consent to your partner engaging in a relationship, that also doesn't keep me from having judgment about it.
We polyamorous types are probably not going to impose "traditional" value judgments about sex and monogamy, but that doesn't mean we are going to always withhold judgment (so long as there is consent). For example, I reject value judgments rooted in patriarchy, and I look askance at bougie sexual mores. That doesn't mean that anything goes, though, or that "consent" is some sort of free hall pass.
You write: One of the most compelling arguments for non-monogamy is the appeal to consent: all else being equal, as long as everyone involved gives their informed consent to a particular relationship configuration, that configuration is ethically acceptable, at least on its face.
I don't know. Is everyone being kind to each other, and thoughtful about the happiness of each individual involved? Is anyone under some sort of duress? Is everyone on equal financial footing? What about gender, class? Personal life goals?