I think the world would be better off, generally, if people took a commitment to the public good more seriously than a commitment to their word. People should not enter into contracts that could lead them to act against the public good, and should feel free, without any guilt, to ignore any contract (or part thereof) that is against the public interest. This applies most visibly to contracts on confidentiality - I have no doubt that most of the material on Wikileaks is collected from disclosures forbidden by contract (and in some case forbidden by criminal law). Nontheless, we should laud the site for the public good that disclosure has given us in the vast majority of their content. Personally, we should hold that to directly stab at the public good is a form of treason, a form more serious than to betray the nation.
Should we always avoid these contracts? In the more unconscionable contracts, no, because that would just hide this knowledge from those that would shout them to the world. In many cases, we have an obligation to sign contracts and agree to things that we have no intent of fulfilling. When that is not necessary, particularly when something would not easily happen without us, we should abstain from involvement.
The public good is a fuzzy thing, but at least as individuals in such an ill-formed society, we are better off seeking something that's not quite defined than accepting something much lesser that's formal - the difference is akin to the difference between seeking someone to love and seeking a prostitute.
Any notion of personal honour that would make us more concerned with our word being inviolate than what is good is a notion we should dispose if we are to be judged good. Yet, in a broader sense, we should try to be forthright about who we are when there are no immediate consequences, and we should also try to reshape society towards a situation when there would be little need for things like this.