No, this is inaccurate. If it's a fully refundable fare, generally there is no requirement to cancel the reservation prior to departure. It is non-refundable fares that typically have the language in the Penalties section of the fare rules "TICKET IS NON-REFUNDABLE AND HAS NO REMAINING VALUE IN CASE OF NO-SHOW" which means if you don't cancel/change by departure time, you lose the value.

Refundable fares don't typically have this language, and can be refunded at any time within the ticket validity. But always a good idea to read, and save/print/PDF the full fare rules.