Safeway Reinvents the Gregorian Calendar

Safeway usually hands me coupons with my receipts. The coupons mostly wind up being for products I don't even use. The Safeway I typically frequent also sells Jamba Juice and after my last purchase I actually received a $1 coupon from Safeway to use the next time I wanted to buy a smoothie from any participating Safeways. Of course, coupons have fine print. The coupon stated in a couple places that it would expire on 04/30/10 and that the limited time offer would end 4/30/10, but the fine print said the coupon would be valid until 4/31/10. Where this 31st day of April is coming from I have no idea. Even when it's a leap year, there's still no April 31st!