By all accounts, it really sounds like these things have the same stock and the same finish as regular bikes. If that's the case, playing around with them for too long can cause them to clump and wear out. If this happens to you, putting them in the box for a while should take care of the problem. Another quick fix is to give them a good riffle- or faro-shuffle, that rearranges the positions of the cards and can help sticking or fan-splitting. Also, don't even think about eating any kind of junk food before handling these unless you've washed your hands. The UV500 can stand up to that, but the air cushion doesn't have a prayer against even minimal amounts of grease.
The deck in the fridge idea is definitely NOT a good one if you live in a humid environment. This is because as soon as you take the deck out of the fridge and it hits the warm, moist air, it will instantly absorb a ton of moisture, which is not good for the cards.
