Exactly - charities need as much as exposure as they can so if someone like Beckham can raise your awareness then all good and well.
People are carrying on like's he stolen from them!!
Look at Joe Hart with the little boy with cancer on Sky Sports last month - Cancer Research were probably glad of the extra coverage they got from that.
I'm already well aware of the many charities, but I agree they need exposure. However, many are doing that pretty well by themselves without the celebrity involvement, for e.g, Cancer Research. They have their own charity shops in most high streets and many people go into them.