Hi Don,
Interfacing an autopilot to a distant waypoint, possibly relying on electronic charting/software alone... Depending upon the scale/zoom range in use, even some pretty big piles of rock can simply vanish from the screen...
Plotting their course to Ensenada on the appropriate paper, even the sleepiest navigator might have noticed that island on their track...
Hopelessly Old School, I know...
best regards,
Jon