Internet Security Systems research analyst Michael Lynn was scheduled to speak at the 2005 Black Hat conference about a flaw in Cisco’s routers that was a major security threat.
Just before he was to speak, Cisco threatened him with legal action and his company decided not to give the presentation.
He promptly quit his job and presented the information anyhow. This move earned him a job with one of Cisco’s competitors as well as much respect from his peers.