I was passed this today. I can find no reference on the Internet about it, apart from repeats of this bulletin. It smacks of a hoax to me but it is theoretically possible.
I think it would be unlikely that a hotel would NEED to keep this information on a key card but it wouldn't suprise me if they did!
I have emailed Kent Police to check with them but I won't be holding my breath for a response.
If any of you have any further information that could clarify this, it would be great. If anyone has access to one of these cards and a card reader, that would be even better! It is unlikely I will be staying at a hotel for a little while yet....