I think in the end Comic Relief gets about 25-50% of the value, less for things like US pennies and more for things like JPY 500 and CHF 5.
For an organised charity, that's pretty good. Many large charities get about 15% after all the administrative costs.
The best charities, by far, are the little unsung heroes who work directly with the poor - the little band of Sikhs among the T5 Baggage and Loading teams who collect money and buy and repair old ambulances and medical kit to ship overseas, "Papa Smurf" at Gatwick who collects toys, puzzles, sports equipment and bits of old technology to take to a childrens' hospital and orphanage in Zimbabwe etc. The airline industry has loads of golden hearted individuals - bless 'em!
That's happened at BA, too. I think that there should be a special place in hell reserved for people like that.
I knew the girl who did that, based at Gatwick. She used to be on check in and was over the moon when she was accepted as cabin crew. I don't believe for one second that she was intentionally stealing as the donations were still sealed in their pouches, untouched - I think it was more of a cry for help and I believe our managers thought so too! Stealing, of course, almost always results in dismissal whoever you work for, and BA have a history of referring dishonesty to the police as well, but in this case, I hope she got herself sorted out and is no longer headed for Old Nick and the Fiery Furnace!