Threatened with legal action - For trying to expose the vulnerability.

I guess the researcher should create an exploit and sell it in the black market.

Remember:

1. Any system that claims to be secure but does not allow to be inspected is WORSE than a insecure system.
2. In security what you don't know CAN HURT YOU.

From the article:

While the vendors' descriptions made large claims about how secure their cameras were, Gnesa found undocumented backdoors and remotely exploitable vulnerabilities

He would have presented all of this information at next week's conference until he was threatened with legal action from an unnamed vendor of one of the cameras.

Garcia and a number of other researchers discovered that millions of vehicles were vulnerable to remote hacking and effective immobilisation.
When they presented their research to Volkswagen in 2013, they were promptly smacked with an injunction in the UK high court and their work was suppressed until recently.

For more information:
http://www.scmagazineuk.com/security-expert-cancels-talk-on-back-of-legal-threat/article/444136/