Eyeballing?
Sounds great when everything is working to plan. But can you beat an eyeball when it ain't going to plan? I mean a plane turning left instead of right. Looking out on City Airport in 180 degree 3D reality colour the anomaly should register. But will it register if it isn't on the screen the remote controller is currently looking at?
But then does anybody look out of the windows these days? I've never seen anyone cleanin'em