It's actually the font name that is sent in the packet containing the message data, so even if you don't have their font, you will still be able to know the font name (and thus send messages with that font).
That being said, making such a script is extremely arduous and I doubt that anyone here will spend a lot of time making a script like this for the sheer novelty of a 15 second laugh.
However, it has been done by MessengerDiscovery (though use it at your own risk).