I was wondering if the balance on a gift card was actually written on the magnetic stripe or if its in the store's computer database. I think the card just gives the account info and that directs their computer to find your balance, but I need to be sure.

im 99% sure that its on the computer, not the card, because you can call a number on the back of the card and check your balance. also, changing card data is kinda hard to do. make that 99.99% sure.

The balance is, indeed, in the store's database. There may conceivably be a way to change the ID number on the actual card to something else, but I don't know what it is.

There's a lot of TFs on this type of thing in the tech section.