At work I’m using the Dell Latidude E5500 notebook, running on Debian testing. Today, I had some issues with Xorg which could not detect my keyboard and mouse, so I tried to do the Magic SysRq tricks (you can read about it at Wikipedia). Unfortunatley, to press SysRq (on F10), I had to use the Fn key, so if I pressed e. g. Alt+Fn+SysRq+U, the U was detected as keypad 4 because of the Fn key. Luckily, it works as intended if you release the Fn key after having pressed Fn+SysRq, so to remount all mounted filesystems in read-only mode, you would actually hold Alt, hold Fn, hold SysRq, release Fn, press U.

Never thought notebook keyboards were so smart :-)