In the FAQ, it says "If the price at the bowser goes lower than your locked in price, don’t sweat it. You’ll only pay the lowest price on the day you fill up."
Do people scan the voucher and automatically receive the lower price, or not scan the voucher at all?
I'll scan the voucher even if my price is higher than the bowser price because that way you can lock in again for another week. The POS system will automatically apply the lower of the two prices.