I know what you're saying, but I don't really agree with this to be honest. If a flight changes, I'd expect the airline to let me know, particularly if it's as significant as a cancellation and rebooking to an earlier flight.
I don't think we should have to keep checking flight status on the chance that something has changed.
I don't know when the original flight was cancelled - I presume on the day. This particular example was a bit of a perfect storm in that regard - I couldn't have checked the booking (online, anyway), as the QF website wasn't working properly from the night before my flight until at least the time I left for the airport. It kept asking for login credentials over and over again, and wouldn't actually progress to the "manage your booking" page. I know this was an issue, because others on FB were having the same problem - I was trying to get in, because I was trying to OLCI.
Anyway, water under the bridge for me. I'm enjoying a nice single malt at the moment