Should celebrities get involved in global politics?

American film actress Sharon Stone has put her foot in it with these comments on China. Essentially saying the Chinese earthquake might be punishment for the country’s policies on Tibet. Are celebrities better off keeping their mouths shut when it comes to geo-politics? Or do they bring much needed attention and publicity to political campaigns? George Clooney has tried it with Darfur. Sean Penn with the Iraq war. Do we care what they think?