This is not the most helpful of AICs and clearly, in the case under discussion, it is misleading. OK, I'm being kind - it seems to me that the AIC is wrong.
If you look at the actual legislation referred to in the AIC it says:
For the purposes of an aeroplane taking off from or approaching to land at an aerodrome within Class B, C or D airspace, the visibility, if any, communicated to the commander of an aeroplane by the appropriate air traffic control unit shall be taken to be the flight visibility for the time being.
Will a legal beagle please correct me if I'm wrong but a balloon is not an aeroplane (nor is a helicopter). My understanding is that rule 24 (3) does not apply to any aircraft, just aeroplanes - something that the AIC glosses over.
One is tempted to wonder whether whoever in the CAA wrote the AIC understands the legislation that they are supposed to enforce. Or have I got this completely wrong??????