It happens every so often that a user decides to change their birthday for the attention. I don't know if it should be an issue for consequences as much as for prevention. Birthdays formerly were immutable, but obviously not anymore.
The whole dishonesty thing is a complicated issue.
Uh a birthday isn't going to give away anything private, just don't put one anyway if you feel that way. And this isn't what the tread is about. He's talking about people who change their birthday every day to get noticed. We won't know if you're simply faking your birthday anyway.
I've never noticed this, but if it's really that bad maybe hull could make it so you either: can't change your birthday, can only change it a certain amount of times, or only able to change it once a month or something.. if those are possible.