The buttons to use abilities on the command card are disabled.
If a player does not know a hotkey they can click the command card and it will broadcast to other players that this player does not know the hotkeys for unit x. There will be a 5 second delay and then the players command card is activated for 5 seconds before being dissabled once again and the unit they were using takes damage equal to 20% of it's life.
The map is called "hotkeys only Shattered Temple" on the US server.
It was made by request of a clan leader and is only a quick and dirty solution but if anyone wants to use/steal/modify feel free to do so.