Don't know if this is tongue in cheek or not but I get messages that say they can't serve requests all the time. Service might not be entirely down but it definitely isn't serving all traffic more often than that.
It's a best effort approximation - this status page is automated via external uptime monitoring.
It won't catch a 1 in 10000 5xx error, but it'll catch the whole site being unavailable for several minutes.
There have been several occasions recently where it is in read only mode.
I saw that it was in read only mode for a while. Couldn't have been more than a couple of minutes though.