It has always been the last sunday in august, going into september. I just question the actual date...not that i suspect its a false rumor (just to clarify). When i worked there the store manager wasn't even aware up until a week or less before the sale.
And about competetion...
Everyone's area is different, but the store i was at was the second highest volume of sales in the state. And even though we stocked up on around 15 55gals...maybe 4 or 5 sold on the first day of the sale.
No special orders, probably not oceanic, and managers tend to hold to the sales terms as its such a big sale.