That's a great idea to have them split the bill at check out too, they didn't tell us about that option.
ILoveMyDVC: we used a Disney Gift Card. You can buy them (using your credit card or whatever form of payment you wish) everywhere on WDW property, before you go at a
Disney store or online at the Disney web site. If the card is lost or stolen, email/phone contact them and the card will be 'frozen' and any funds remaining on the card can be transferred onto a new card if you provide the first 12 digits of your card number. An original proof of purchase receipt (the letter that accompanies your card) for the Disney Gift Card is required to transfer the funds onto a new Disney Gift Card. Unfortunately, any funds spent before the card is reported lost or stolen cannot be recovered.
They are supposed to 'freeze' lost Key to the World cards as well, except my mom lost her room key & got another one. Later she found the lost key (never reported that she found it to a CM) and was still able to put charges on it, use it as her park ticket, entry in the room, etc...which really had me concerned!
I love using the Key to the World and not having to carry anything else with me, but the Disney gift card ended up being pretty great too and helped me to actually budget things out a little better since every time I used it they would tell me (and the receipt listed) how much was left on the card.