If holding oil for speculative reason became illegal, I'll bet we'll have a huge selloff followed by a surge in demand as everything from airlines to power plants spend billions locking in a price. We're currently at 110, we didn't get their by speculation alone.
And at times there are more short speculators than long which keep the price down, but no speculation is no speculation.
We would also see oil shortages during hurricanes, war, or any other disaster which will interfer with the flow of oil. Let's face it, speculators are the ones which enforce the laws of supply and demand in this case.
If a class 5 hurricane had a 20% chance of hitting the buk of the oil rigs in the GOM...
and if there were no speculators...
the price of oil would theoretically not change since speculation that the oil rigs would be destroyed would be illegal.