The following video shows that if you try and add the one and only Hideo Kojima as a friend via PSN, the ID is instantly transformed into Old Snake. Could this be Kojima's real account, or just a bit of fun?
To quote from runandgun: He's denied me like 20 times in 6 months.
It takes anywhere from hours to days to get denied... also I've seen a short video of a guy being accepted by Old Snake and the account playing Lost Planet. So it is most likely not a bot and instead someone's genuine account.
Just FYI - this isn't Hideo. I can set mine to say OLD SNAKE right now.
It works for any Japanese account but has been disabled for other regions.
In your JPN account, just go to edit profile, and you can set your handle to be different from your account name (and I don't mean your email address - I mean your PSN name) and after you've been added as a friend by someone - the chosen handle will display instead of your PSN name.
Not all games support the displaying of the handle instead of the account name but some do.