The accuracy of cancelled flights is still really inaccurate. A google search of the flight number shows canceled for multiple flights every day but the website as well as FlightXML shows the flight is still going. There are a few hints the flight may be cancelled such as missing gate info and or presence in FindFlight.
For example, as of writing the entire FlightAware platform thinks AAL1888 on 5/16 is departing in 25 minutes. However a google search of the flight number shows cancelled from the Google API. If google knows its cancelled, how come FlightAware doesn’t?