Well, the G15 is usb, so that won't be a problem... as dwg said, hot swapping anything with the ps/2 is a big no no. Not sure about fuses, but it will fry the port on the motherboard. So if you accidently unplug it, if the mouse still works, just shutdown the computer, then plug it back in and start back up.
Also, might be a good idea to check the pins on the connector to make sure none of them got bent or pulled free when you yanked the cord out.