My understanding is as follows: Geoffrey Jackson could have proclaimed that celebrating your birthday while smoking a stogy was in perfect harmony with scripture, it would actually not mean a thing and here's why.
Unless the governing body met and backed up his claim with a vote and subsequently had the 'new light' published, its just one mans opinion.
The governing body are only G.O.D. when they meet. Sort of like how the power rangers can only transform into Megazord when they physically get together. Or like the Pope who is only infallible when he makes a papal decree.
There are rules to these things you know.