First off, donations to charity are supposed to be for the charity, not for the benefit or publicity of the donor. Publicizing "I gave xxx to charity" like Bill Gates and others do is just another form of buying publicity.

Two good ways to encourage donations to charity:
1) Encourage them, and offer to match any donations
2) Collect donations and send them in, as L.A. did. If you are a controversial person, use a middleman to make the donation anonymous.

If L.A. does this again next year, I hope he finds a way to funnel the money to the charity without his or any other controversial name attached. After all, the kids are more important than name recognition.