The song playing (Paint it Black) was a little too loud, so I picked up my trusty Apple Remote and turned down the volume. Both the iMac and the MacBook picked up on the signal and the volume on both was adjusted. Oh, the horror!
There is a simple way around this though, just pair your Mac and your Apple Remote following these instructions. This way a prankish Mac user (I'm looking at you, Woz) can't go around putting your Mac to sleep with the remote and all the Macs in your room won't respond to the same remote.