In the absence of a genuine ticket to the real event, Facebook users are encouraging each other to reveal their Royal Wedding Guest name.
Here's a typical message that is currently being spread by well-meaning users across the social network:
In honor of the big wedding on Friday, use your royal wedding guest name. Start with either Lord or Lady. Your first name is one of your grandparents' names. Your surname is the name of your first pet, double-barreled with the name of the street you grew up on. Let's do this! Post yours here. Then cut and paste it into your status.
Lady Edith Spanky-Rushmoor
Do you see the problem?
By playing the game, you might be unwittingly making life easier for identity thieves and hackers.
Look at it this way. Think of all the websites which ask you to give it a "secret question" which can confirm your identity in the event of you forgetting your password.
If you tell everyone your Royal Wedding Guest name then you are giving away information which might help someone break into, say, your email account.
So, here's my advice.
Firstly, don't post this kind of personal information onto the internet - the few seconds worth of amusement you may get by telling people your Royal Wedding Guest name are not worth the potential pain of having your identity stolen.
Secondly, when websites ask you for a "secret answer" to reset your password... lie. You don't need to tell the truth when you're asked by a website what your mother's maiden name was, or the name of your favourite TV show. So, say something random but memorable that no-one is likely to guess like "Xena Warrior Princess" or "Artichoke Sandwich".
If you use Facebook and want to learn more about threats, you should join the Sophos Facebook page where we have a thriving community of over 70,000 people.
Of course, if you do happen to be one particular couple getting married tomorrow, you're not going to have any chance keeping your grandparents' names secret..
Hat-tip: Thanks to Naked Security reader Paul who brought this particular issue to our attention.