I'm not sure how, but early DTT set top boxes had some component installed that could "inadvertantly" call the search and rescue lifeboats out
https://www.theguardian.com/media/20...casting.uknews
http://news.bbc.co.uk/1/hi/england/devon/4712122.stm
This quite likely isn't just a case of "spurious interference" either, since it happened on more than one occasion! It makes you wonder what kind of telemetry they have installed... albeit maybe temporarily misconfigured...