You will find that the registration form which you sign on check-in has wording to the effect of "I agree that my personal liability to pay for the room is not waived and I authorize the credit card I have placed on file to be charged for the room rate and any additional charges in the event that another party fails to pay for the room as arranged".

While it might be reversed on calling your card company, it would be a temporary reversal and there is a possibility it would be reapplied when the hotel sends the card company a copy of the agreement you signed.

I do not have any evidence of this ever being relied on, but all I have ever said is that people taking the risk (and it is a risk) of booking rewards more than a year out need to be aware that they might end up with a lot of personal inconvenience. Equally, they might not. It is a risk.