"Closed for Inventory"

So I went to Radio Shack to buy watch batteries (of course -- does anyone go to RS for anything else?) and found them closed for inventory. On a Sunday afternoon.

Why? Why would you close your store on Sunday afternoon, presumably one of the two busiest times of the week? Wouldn't it make more sense to do inventory on, let's say, Tuesday morning? Or Sunday before noon, when YOU'RE CLOSED ANYWAY???

I hate Radio Shack.