Ah, but we could cite Cliff's Facebook page as evidence that he is disputing the reports of his own death. That's at least strong enough to put his earthly existence in the "debatable" column.
> Self-published or questionable sources may be used as sources of information about themselves
Clifford Stoll's own Facebook page saying he's not dead can be cited on Wikipedia, even if Facebook itself (or Clifford's non-expert opinions) are unreliable