. . . err, that'll be 'Don't assume - check' then.
It might sound as if I'm just trying to be smart.
But this has been proven time and time and time again. Someone mentioned above about missing the basics.
The times I've heard that pilots (there are really only pilots left on the flightdeck these days) don't appear to be taught the basics anymore. There is a lot less mental effort required to keep up with (or better, one step ahead) of the aircraft.
Glass cockpits give so MUCH information, it's easy to get swamped by it or complacent because there's little need to think. Ergo, often people (pilots in this case) don't.
You HAVE to check, if you don't - then nobody WILL and we see it here. Fortunately nobody was physically injured here.