No more monitor out of scan range
It can be very frustrating when a PC decides to send a signal to a monitor that is outside its scan range. Yes, the systems try hard to avoid it, via things like plug and play EDID information on monitor specs, and reverting changes to monitor settings if you don't confirm them after a few seconds, but sometimes it still happens. It happens after monitor swap, it happens if you don't have a monitor turned on when you boot or if you have KVM switch that doesn't talk about the monitor.
The result can be frustrating. If you know how to reboot your PC without seeing the screen you can try that but even that can fail.
So I suggest that monitors be a bit better about signals that are outside of their range. If the dot clock is too fast, for example, consider dividing it by two if the electronics can handle that, showing half the pixels. If there are too many scan lines, just show as many as you can. The bottom of the screen will be missing, but that's better than no view at all. If the refresh frequency is too high (though usually that's because the dot clock is too fast) you can skip every other frame, for a very flickering display, but at least not a blank one. Whatever you can do, you can save people from hitting the reset button.