Quote from black diamond:
If you are getting a short with oil to cover, the price has to drop to the point where he is indifferent between sending you oil and buying back the contract to let you roll. Otherwise there is a shipment of oil with your name on it and a big bill in the mail.
I think we can discuss at length on how theoritically arbitrage with the physical would bring prices in line if speculators were really running up prices to excessive levels. Obviously even people in the futures trading business don't come in agreement on this issue (see Santelli vs Bouroudjian debating) although the majority support the view that exonerates them.
It's possible that arbitrage does not work as well in practice I don't know but the the fact of the matter is you have a whole new class of natural buyers coming in (long only funds) it must inevitably drive prices higher, it's just like stocks. Stocks go parabolic purely on momentum and herd behaviors and once it goes parabolic fundamentals take a back seat to the point that prices are moving for reasons that have absolutely nothing to do with fundamentals and wealth is transfered to the insiders (in this case the oil sector companies) with no basis and merit whatsoever for that transfer. Its' a Ponzi scheme .