Just a warning about an aspect of using these that I hadn't considered... don't forget to apply them at check-out! I after a one night stay at the MCO Hyatt, I checked out as usual and didn't realize until I was on the plane that I had totally forgot to use the dang certificates. I had them all ready to go in my bag and everything. Maybe it's because it was 4:30a and I was still half asleep.