> But what if the otherwise loathed real name policy could
> be turned to service this particular need?
The link between a real person and a Facebook account isn't secure - I could make an account with your name today without too much stress (no need to provide ID unless Facebook thinks your name isn't a real name).
I think the grandparent chose the wrong end of the stick with relating this to "famous" people, which, in turn, threw you off.
Sure, you can register an account in my name, but there are quite a number of people who will not be fooled: people who actually know me. People who know me in real life can tell whether an account is real or not, because they can tell whether I post about things I do, whether I post pictures that are...well, me.
In that case, they can be reasonably sure that the account in question is, in fact, my account. If I attach my GPG key to this account, they can thus also reasonably assume that the GPG key belongs to the account that belongs to me. This essentially gets you the online equivalent of a key-sharing party.
The link between a real person and a Facebook account isn't secure - I could make an account with your name today without too much stress (no need to provide ID unless Facebook thinks your name isn't a real name).