I have a room booked in Indianapolis next week for 2 nights for the Indy 500. I booked this room 10 months ago at a rate of $109 per night. The cancellation rate on my reservation currently says cancel at least 1 day in advanced to avoid the penalty.

I received an email from the hotel's operations manager this evening saying that because this is a special event, and per Marriott's terms for special events, they are charging me a non refundable one night stay.

I am 99% sure I will be there those nights, but how can they change the terms and charge my card on file the non refundable rate for one night?

This is more of a curiosity thing that got me wondering and not a huge deal, but wanted to see what the experts say.

Here is the email:

Welcome Race Fans!!!!

We are excited to have you back at the Indianapolis Airport Courtyard this May for the 100th running of the Indianapolis 500.

Currently we have 1 king room reserved for you at a rate of $ 109.00 plus tax for 2 nights starting May 27, 2016 and checking out on May 29, 2016. Per Marriott’s booking rules regarding special events, we need to place a non-refundable deposit of one night’s stay to continue to hold the reservation by May 20, 2016. I will use the card you inputted when guaranteeing the reservation. If you would like to use another form of payment please contact me either by telephone or e-mail. Changes can be made to the payment type at arrival.
It should be an exciting race and we look forward to your stay at the Indianapolis Airport Courtyard!