I would love to see in 24 years of the current BBC blocks logo another example of where the logo has been altered or changed because of failure in brand management.
In addition to Spencer and gottago's examples, there are countless examples of incorrect versions of the BBC logo being used for the logo fade in-fade out at the start of a programme. I've seen versions where the logo was squashed, where the letters were filled in and where they'd clearly tried to make their own version - often ending up with square boxes and Gill Sans Regular.
BBC Films have used an incorrect version of the BBC blocks for years and nobody has done anything. Every version of the BBC News graphics since 2007 have not adhered to the guidelines which clearly state that, if it is placed in a box, there must be at least half the width of one block between the logo and the edge of the box. The new all pink BBC iPlayer logo is in violation of every version of the BBC logo guidelines since 1997 which have all stated that the logo must only be in black or white.
Frankly, whoever is in charge of BBC brand management takes their eye off the ball a lot.