The Chess world actually went to far by forcing the female chess player to wear hijab. Even if this has to do with religion, one still has to feel comfortable by wearing the chess sports attire. If anything she could have been allowed to wear another casual cloth instead of the Hijab.
In international sporting events there should be rules that take into account a variety of cultures. In some cultures, a woman must wear a Hijab; however, in American culture, telling a woman she must cover herself is seen as very offensive. Ultimately, the woman should be allowed to dress as she feels comfortable, with the same rules as men.
The world chess championships are coming to Iran, which has led the governing body of chess to force female players to wear hijabs while they are in the country. Players have reacted with horror and have declared that they will boycott the championships as a result. I actually think that it was a smart move on the governing body's part: Iran is a sensitive country so wearing the hijab while there is a sign of respect.
It's just good manners to comply with the cultural mores of the country, society, community, even the house of wherever you visit. You go to a fancy restaurant, and they require men to wear jackets. You go to a store and you need to wear a shirt and shoes or they kick you out. You don't visit the Vatican in shorts. In Iran, they require women to wear hijabs. It's custom, it's respectful, it doesn't really hinder or hurt the women. If the women don't want to, they don't have to go.
The mistake is from the event organizers who chose this location without consulting with their female members.