I knew someone whose grandfather left his estate in part to his daughters and in part to the Lions club. Because of poor wording in the will, the Lions club got it all after taking the matter to court, and his daughters got nothing but chattel in the home. There was a lot of land and money in the estate.
Personally, I would never name a charity in my will. If I'm feeling charitible and have no loved ones, I'll leave what I have to an individual, even a virtual stranger, who is in need.
W