[GauntletWizard]

Mark Zuckerberg sorta did so- he had a Regular desk in a semi-regular building (that floor had some more security presence, but your standard badge would get you in, and you could walk by his desk row, though I definitely got the impression if you tried to linger or bug him security would step in rather quick). He had a private meeting room right behind him, but there were plenty of times that I walked by and saw him at his desk.

All that said, I don't think that's the norm even at Facebook, just a carefully maintained illusion.