When this command is pasted into a command block (and powered by redstone), it will notify ALL players if someone is in Creative mode! Players in Creative mode will receive this message: WARNING! All players have been notified that you are in Creative mode. Players NOT in Creative mode will receive this message: WARNING! The players [player username] are in creative mode. Please note: This machine says this message 20 times per second, the chat log WILL be spammed.