Earlier quoted context omitted.
Same. It's weird how I always find out that GitHub is down before GitHub does. Took 15 minutes before it appeared on githubstatus.com
All these monitoring rules are of the format "when 500 errors > baseline for x minutes". Otherwise you'd have monitoring alerts every second. So it is normal for users to already see errors before github officially counts it as an outage.
If the first they hear of an outage is when user requests start to fail, then that's a failure in their monitoring as well.
But effective monitoring is harder than people assume.