Should one fulfill unfair contracts? This is an important question in political theory. The answer of the network society is quite simple: One should not, but in this case one has to face the consequences. And the consequence is, in general, an entry in the black list, which will never be removed.
This seems quite rigorous. But it really isn't that rigorous: Because, if the contract was really unfair, why would anybody care about your violation of the contract? There is no obligation to boycott anybody on the black list. The black list is simply a source of information. The information it contains, in this particular case, is that you have violated a contract. It contains, as well, the conditions of the contract you have violated. Thus, everybody can judge himself if the contract was really unfair.
But there is a problem which is not as easy to solve: It is the problem that many people will use robots to evaluate others. How can a robot distinguish a fair contract from an unfair one? That's not easy. But if there is no easy solution, most people may not care about this - they will simply handle the violations of unfair contracts like violations of fair contracts: They don't lose that much, only a few potential clients, which is far outweighted by the advantages of using robots to search for appropriate clients. Thus, those who violate unjust contracts may be handled by a majority as if they have violated a fair contract.
Let's note that there are some other important problems where automatic evaluation is not only possible, but defines a certain improvement in comparison with the current rules of the state: Each entry in the black list contains three dates: The date of birth, the date of becoming a member of the network, and the date of violation. This allows everybody to decide himself about the age at which responsibility starts, who counts as a newbie, and which violations he ignores because they happened long ago. These decisions - simple numbers - they can simply give their robots, and the robots can automatically ignore all entries in the black list which appear irrelevant.
It is more problematic but nonetheless comparatively easy to evaluate the seriousness of a violation. The record of course also contains information about the rule which has been violated. Now, if the rule is part of some convention or penal code which one finds important, one can also assign some seriousness to such a violation. In other cases, one can use the penalty as a measure of the seriousness of the violation.
But all this fails for unfair contracts. The unfair contract cannot be recognized by some number, and it will not be some widely used convention. As well, it may be the much too large penalty for violating it which makes the contract unfair. So how can one distinguish fair from unfair contracts in an automatic way?
A quite simple solution is a specialized arbiter who evaluates the fairness of a contract. Those who think they have violated an unfair contract may appeal to such an arbiter. One should not think that this arbiter changes anything for the other participants. It also does not change anything about the record in the black list. All what the arbiter does is to manage a private list of black list entries which, in his personal opinion, are violations of unfair contracts.
But this gives everybody else an easy opportunity to let his robots distinguish fair from unfair: Your robot gets your list of fair arbiters, and then looks, for each relevant entry in the black list, if this entry is listed as unfair by these arbiters.
There may be different such arbiters, and they may have different criteria of fairness, therefore, everybody has to decide himself if these arbiters and their criteria for fairness are really fair.
But, of course, this solution is not cheap. The arbiter has to be paid for his work. Thus, violating an unfair contract will not be without costs.
Moreover, there will be costs of another type: There will be lot's of people who nonetheless refuse to cooperate with you even if all arbiters accept that the contract was unfair, maybe because they don't trust any of the arbiters or maybe because they are simply too lazy to think about this. Nobody can be forced to cooperate with you, and if somebody decides not to cooperate with anybody from the black list, it is his free decision.