It might also be worth paying attention to the future fortunes of attendees who seem obscure. Bill Clinton was a conference attendee in 1991, as a mere governor of Arkansas, a year before he was elected US President. Tony Blair was only a shadow minister when he got his invitation – (you can’t apply to attend, you must be invited) – in 1993. Conference organisers have previously insisted there is no conspiracy to crowbar their chosen people into top jobs, they just have excellent talent spotters.
Note, however, that those examples are a bit stale now. More recent examples would be more powerful. Or maybe the Bilderbergers are losing their influence, or touch? (cue the stone throwing by conspiracy theorists!)