Highly doubt it will work. Law of supply and demand works in the oil companies' favor. Even if you don't fill up on the 15th, you'll have more than the normal amount of people filling up on the 16th and 17th, offsetting any "loss" that might be incurred. Plus, there's also something in Economics about how price increases occur rapidly but price decreases are delayed and slow to occur (sorry, it's been a year since I studied it)

Plus, the notion of a 30 cent overnight drop in gas prices is rubbish. More likely a 30 cent overnight increase due to some political instability.