I often ask at Disney and other hotels how much it would cost to pay for an upgrade when I check-in. It's one thing to ask for a free upgrade, but the check-in person seems to respond better when you ask about paying for the upgrade. Half the time they just say the difference between my rate and the rate for the upgraded room (and that is the worst that can happen), but the other half they usually offer me the chance to get the upgraded room for a smaller rate increase than the listed one and a few times (more times than you would think) they have given me the upgrade for free. It doesn't hurt to ask and its not as though they are going to give you a bad room or something just to spite you (in fact, usually if I don't pay the difference for the upgrade, they seem to try a little bit to get me a nice room) they might just roll their eyes a little.