So I certainly think it makes sense to give out real data, iff you plan to use the service as intended.
That said, the bigger problem is that Google happily accepted his date of birth in Google+, added it to the Google account and afterwards locked him out of every Google service. That's crap. And it just proves once more how Google aggregates all the data about you. If I fill in an innocent field on a 'fun' service, should it really have consequences for (or even be connected to) my main online identity?
Of course, I didn't fake my interests/gender/etc. but I've never been in the habit of storing age/location info with a private service; it's available publicly anyway, but you have to use inductive reasoning to link the data. If you want people to know your birthday, I don't see why you can't just tell them in person or email or whatever and leave the "official" fake birthday what it is.
This could be fixed by using the correct date but putting an earlier year.
Well said, I think the most worrying part is that google didn't even warn us it was going to use this information across all its services, this is the first time I'm actually disappointed by google.
I've been using January 1st, 1975 as my birthday ever
since I started using the internet
Oh, lots of times I use the current year just for fun.I press page down a few times when I tab to the year field myself!