Do most people who do charity work do it for the free publicity on TV and Newspapers, so they can drum up more business?

I suppose some would do that. Personally, I have only done it for charities that I care most about and do it to help them out. It would be a bonus if you can get the charity to get you some positive publicity. One problem I have found is when you get publicity for doing something to help a charity, you suddenly are bombarded with requests from other non-profits wanting you to do the same for them. That's when learning to say no becomes a challenge.