Actually, it will still display their native res at really high resolutions.. just not all of the extra..
Example: my dad's 17" LCD monitor supports 1280x1024 max.. now I can set windows to 1600x1200.. but the monitor is only showing 1280x1024 of that at any given time.. I can move the mouse around to move which location out all those 1600x1200 the monitor will display...
so it's harmless for that monitor.. I don't know if nate's works the same way, but thats how my dad's does.