There's a whole lot of speculation in this thread and a lot of it is wide of the mark. I don't know a lot of what is being planned in terms of coverage, but having worked for the BBC for about seven or eight years and having been on a lot of different programmes as a guest from the podcast, I can at least talk about the 'process'.
The above quote is exactly it.
When you're working on a news programme or a talk radio station, you have several types of story -- sometimes you know something's going to happen and roughly what's going to happen when it does. Take something like the Budget. We know exactly when it's going to happen and roughly what's going to be in it, so we can start lining guests up accordingly beforehand. The last thing you want is a lot of airtime to fill and nobody available to do any analysis.
With the charges, I can only speak for my experience at 5 Live, but... nobody knows what the outcome is, nobody knows when the verdict will be delivered, but what we do know is that there will be a full day of programmes that will need to cover the story and they're going to need guests. They're going to need reaction from fans, journalists, financial experts, former players... The beauty of a story like this is that it doesn't actually matter what the outcome is because the guests will still be the same type of guests -- because everyone is reacting to whatever the outcome is.
From the timescales that were spoken about previously, from the comments Guardiola has made about a verdict likely to come soon, this is all just media outlets planning for when it happens. It's not unreasonable for BBC, ITV, and everyone else firing out emails, messages and calls along the lines of: "Hi, when the verdict is announced, whatever day it is, can we give you a call to get you on air for your reaction please? What's the best number to get you on? What type of times are you generally available on weekdays or can we just try you as soon as possible?"
In this instance, if an emailer says they've been 'briefed', it's more than likely nothing to do with the outcome. They've not been briefed on the story by someone outside of the organisation, but briefed by people inside the organisation about the logistics of covering the story.