I have a free night certificate in my account from US Chase IHG credit card. In the terms it says that " The Anniversary Free Night must be redeemed, and stay must be completed within the booking window dates shown." and the booking dates shows "Jun 5, 2014 - Jun 15, 2015".

I was trying to use this certificate to book a free night in August 2015, and it seems that it works. So my question is that will the hotel cancel my reservation after June 15, 2015? Will I have problem when I check-in? Anyone has experience about this?

Thanks.