It is quite silly indeed. I've never seen a place (before Marriott) where you can't swipe the card and simply check the balance or tender an amount up to the balance. However, to prevent issues, I check my balance online the night before checkout and write it in the envelope sent with the card. Since I'm usually online before I go to bed, it's a very small inconvenience to prevent a larger inconvenience at checkout.
I guess we could add thise to the pet peeve thread.