I'd be very concerned and questioning it if you did not authorize charging privileges. They do that when charging privileges are authorized to make sure you will be able to pay the bill. It could have been done out of habit, or it could be a dishonest person checking before harvesting your cc number. I would put money on the former, but I'd rather be safe than sorry. It could also be in case you make phone calls from your room or order room service, I suppose. I'd just check--no harm in it.
If you aren't checking in (and it really does sound as though you are, as I re-read), I'd really check on it. The only reason they'd run anything on your credit card is if you are making an actual payment and then it would be for the actual charge. They shouldn't be checking your card for validity for any reason. Personally, I'd call Disney AND the cc company.