"The Tragedy of the Commons," Garrett Hardin, Science, 162(1968):1243-1248.
The problem for this kind of property rights is free access (and nobody has the right to restrict anyone the usage of such "open access" resource), and it caused an over-using problem, never the problme of "monopolizing" an "open access" resource. To make it more clearly, Hardin was talking about using the resources of the "commons" more than it is efficient. People used up a common property much quickly and exhaused the resouces before it can replenish itself (if it is a renewable resource). It would be an economic problem if the resource is used up too quickly before we can find a substitute, or use the resource faster than the regenerating/reproduction rate.
Like Cloud Mountain and other Librivoxers are trying to say: nobody owns air and water (and everybody own the right to breath and drink, that is the spirit of PD). Economists might consider there's a problem of over-using the resource of air and water.
Fortunately, no body has a claim to the right of restricting us breathing the air or bottle the air for sale (there were air bar in Europe), or using the water from the sky (at least) and bottle it for sale (if we choose not to drink it and get very thirsty, that is our freedom of choice), or even restrict us singing "happy birthday" in private (not allowed in public though 
). Can anyone imagine there would be a possibility of such restrition someday? If we do not set this kind of rights free, which means "open access" or PD or anything you like, the world would be a nastier place that I would not like to live in.There are some debate of restricting people from a service of convenience: such as someone would wait in a line for you to buy a hard to get ticket for some fee, you get the ticket without wasting your time and you can work more productively and earn more income. A lot of people are willing to pay the fee to get such services. However, our gov't has been debating it for sometime and finally ban some of the services. They argue that one should not do this for profit, so ban the pratice. A lot customers have to wait in line themselves and wasting the time which they can produce more valuable things for the society. Selling LV would be one such practice. If there are customers who are not willing to be bothered downloading/cataloguing nicely/burning CD/DVDs themselves, they can pay their neighbors to do that for them, why would you tell them:"it it not good, it is baned, it is illegal, etc." If one choose to buy, and one choose to sell, and we are in a free society, and I can not figure out why would it be a sin/crime?
If one buys the CD without knowing it is PD material, it is still not a crime. We call it the rent for information. If you are not willing to surf the net and find out what's out there, and somebody search the net and collect the information for you, you save the time surfing (and did something more productively), and you are willing to pay for someone to do the info search/collecting for you, you are paying the info collecting agent a information rent. It would still be a win-win situation. Somebody have done you a service you want, and you pay the fee, and in the mean time you choose the time to do something more beneficial for you (it's your time-management scheme, and it's nobody's business.)
It is just like a dealer's service, housing agent, or a brokerage's services. They collect all the information you need and gaining specialties in that field. We are paying those services without any apprehension or concerns. There are many types of service that we are paying such information rent without realizing it. They are all legal. And we are benefited by the conveniences of such services.
If PD means "everybody can use the resources whatever they like", it is similar to "open access". The only thing that can limit the "open access usage (to solve the over-using problem in economic logic) would be by public consent, if we do not resort to privat property rights ristriction tricks. Economists would prefer some kind of private property restrition ("restriction" is the main point and magic word in this solution), simply because it is quick and effective (but not really a best solution for a world of diverisy in philosophy and beliefs). As long as there is a way to restrict the usage, it is not "open access", and somebody can do a trick or two to get profit, we call this rent-seeking behavior. If it is "open access", the only way to get more benefits is consuming it more than your neighbors' consumption and get more utility from the consumption, because nobody can sell you what you already have (the rights of free access already granted to you). If it is exhaustible resource, then consume it before it's gone. If it is renewable or non-exhaustible resource, then take your time and calculator to find out what the consumption rate is best for you.
HC
