In the US, some PayPass users have been issued with a keyfob unit that is quite compact, but how do you dispose of the unit securely when you get a replacement?
Unlike conventional cards, including PayPass, the keyfob units cannot be cut into bits that easily. On top of that, even if you break the beasties open, it's not that easy to dispose of them reliably.
The problem with the RFID cards, as I've pointed out before, because you don't normally need a signature or PIN code, you can wave a partial card - or even remnants of a keyfob - at the terminal and pay for your purchase quite easily.
Marianne Pizzitola in the US, who dutifully snips up her cards, was worried about how to dispose of her PayPass keyfob from Citibank, but found it wasn't that easy to dispose of the unit.
You can read about her experience here...