There are two major beliefs about the role of judges in a libertarian society. One is that judges should play the role of mediator between the parties of a dispute. The other is that the parties of a dispute agree beforehand to abide by the ruling of a judge. There are other views, but these two seem to be the most common among ancaps.
I favor the first, but I don’t necessarily consider the second to be wrong or without a place in a libertarian society. The main reason I favor the role of mediator is that the judge is meant to help resolve the dispute. It also helps cut down the time it takes to find a “neutral” judge that both parties can agree to. After all, it’s easier to shop for a judge when you know he isn’t going to rule against you.
My view on this is that it would depend on the nature of the dispute. Commercial disputes, neighbourly arguments etc. could be resolved by arbitration. Situations in which you’re being accused of murder etc. might require a more adversarial setup and therefore a judge who is willing to favour either one or the other party. Bearing in mind that what judges and the system they are part of do is deliver a stamp, of sorts, that shows that you went through the correct procedures to have your claim examined. So it’s a social signalling mechanism, in addition to anything else it is.
I think the topic is interesting. Personally, I would only consider consent not to be present if a) there was mind control, b) lack of consciousness or c) a mind-altering substance that literally made the recipient party unable to comprehend to what exactly they were agreing. Some people might have conditions, such as senility or mental retardation, that make them inherently incapable of such an understanding, so they’d fall under the rubric of c), too. Children may also arguably fall under c) until their brains mature sufficiently.
With Bill, I favour the answer given by Gotlucky. He can dispute the doctor’s fee based on what would be “reasonable” to incur in such a situation. On the other hand, I don’t think that until Bill has actually haemorrhaged to the point that he is out of his wits is he incapable of granting consent. With Lorraine again it depends on whether she was drugged to that point.
I don’t find the “norms” thing very convincing. It doesn’t seem very libertarian to me. Just because something is a norm doesn’t mean you consent to it. What if I think the “norm” is unfair, and would refuse to follow it if I was of sound body and mind? Too bad, I guess.
Courts aren’t going to reinvent the wheel for every case. They have to work to an evidentiary standard and deal with what they have in front of them. If someone claims the doctor “ripped” him off whilst in a vulnerable state, they’re doing so with a particular idea in mind as to what would’ve been a fair price for the transaction. Also, in the name of efficiency and to more easily deal with routine cases (or elements of them in more complex ones), courts will likely resort to norms. Now, as was said, you don’t have to consent to the court’s ruling or abide by it but that may have adverse reputational consequences unless you succeed at appealing the decision with another court or otherwise show how the court’s conduct was flawed.
Things like norms of appropriation (i.e. what you need to do to appropriate something), abandonment, age of consent etc. are inherently “grey” areas and will require judicial norms to be dealt with fairly and efficiently.