There's nothing inherently bad about a guest editor. When i had one last year – Elton John, who is a rather more genial presence than those to whom I generally have to present my foreign news list – the result was fascinating, and emphatically not a 56-page paean to his own greatness.
The generally marvellous Today programme, in contrast, has not been quite such a roaring success in the latest edition of its own annual celebrity rotation. The first two of this week's line-up – Lord Coe and Mo Ibrahim – have been singularly uninspiring. Coe, for God's sake, is well known as having all the charisma of a toadstool, and the choices he made were entirely predictable.
Guess what? Seb Coe had a big rivalry with Steve Ovett in 1980. This is the perfect, topical jumping-off point for a conversation about rivalries, featuring William Hague on Pitt the Younger. And so on. Still, the vapidity of Coe's choices did have this to be said for them: as cloying as they were, they didn't get anything controversial wrong.
With Mo Ibrahim the calculus was a little more complicated. Dr Ibrahim, a Sudanese telecoms billionaire, is also behind a $5m prize given to African leaders that is supposed to encourage good governance and the smooth transfer of power – you can only get it once you've stood down. That was the backdrop for a discussion in which the former Presidents of Mozambique and Botswana held forth, at length, to Evan Davis about how they'd done it, while Dr Ibrahim praised their modesty.
This is all fine. The problem is, it's far from the whole story. There's an argument to be made that a prize making the cosseted retirements of the richest people in Africa still more pleasant is far from a symbol of the best things about the continent; and, as our reporter Daniel Howden noted when this year's award was handed out, when it's going to the President of somewhere as irrelevant to the broader picture as Cape Verde the sense that something is amiss only grows stronger.
Was Dr Ibrahim confronted with those questions, in typically rumbustious Today-programme style? He was not. Instead, we got a lecture about the lack of reporting on Africa's good news. Leave aside the strange idea that the news should focus on the mundane at the expense of the troubling and consider Dr Ibrahim's award: the prize has twice not been able to find a worthy recipient since its inauguration in 2007.
And yet no one queried it. This morning's edition features the artist Tracey Emin. If by 9 o'clock no one has asked her whether a child of six could do it, we'd better start worrying about whether John Humphrys has been locked in the cupboard.