According to GalleyFM (and I have heard this from ex-QR employees as well), one unfortunate pair managed to keep their relationship on the down-low until it came to the point of wanting to get married. So like good little boy and girl went to the Boss to ask and both promptly got fired. No idea if the fact that he was flight and she cabin crew had any bearing on it...
Not sure of the truth but it doesn't sound that far fetched, and it persists, so I'm sure it's happened to at least some....
Okay fine have your rules if you don't want your CC to 'fraternize' but to require permission to get married is ludicrous.... Plenty of married crew in EK and the other airline and they haven't come to a screaming halt yet...