Considering that more sound engineers are employed in broadcasting than anywhere else, it doesn't hurt to have an awareness of broadcast practice.
'Broadcast practice' is in fact a term used by the BBC (British Broadcasting Corporation – the biggest public broadcaster in the world). It means that the faders on a mixing console work the other way round than normal. They are closed when they are at the top of their track, and open when they are closest to the sound operator.
The reasoning behind this is that in broadcasting it is the worst thing in the world for a channel to be open when it is not meant to be, with potentially millions of viewers and listeners hearing what they perhaps shouldn't. And it was considered more likely that an awkward elbow would push a fader towards the top of the track than the other way round. So it would be better for this accidental movement to close an open channel rather than open a closed one.
Having said that, the BBC now use what they call 'commercial practice', like everyone else.
And actually, you don't have to watch live TV or listen to live radio, from any broadcaster, for very long before you do hear an unintentionally open channel.
Perhaps the BBC were right in the first place.