FFI, RI, SHS, TPS and CY usually allow cancellation until 6 pm the day of arrival.

Full service hotels on a corp rate often allow cancellation until 6 pm day of arrival.

Hotels tagged as "resorts" often require one day in advance. Often the policy changes due to a local major event, such as a major sporting event or a major trade show.

If not booking on a corp rate, then hotels in major cities often require a days notice, sometimes three days. I have seen a 30 day notice to cancel.

My guess is that you got lucky. Whee, you're a winner!