Notes on verification

Date and guitar-less performance are well corroborated by multiple independent sources including History.com. The specific Berle quote traces back to Berle's own later recollections and appears in several independent write-ups, but no primary contemporaneous source or documented interview citation was found, so it rests on a widely repeated anecdote rather than fully verified eyewitness corroboration. [tier=silver indep_score=0.75 clusters=3 claim_tier=notable | framework convergence=partial on Likely traces back to Milton Berle's own retelling of the anecdote in interviews before his death, repeated across biographical/journalistic accounts (upstreams: Milton Berle's own later interviews/recollections (referenced but not directly sourced)) — publishers independent, evidence may not be | kind=attributed eligibility=medium]