Being distracted by a cell phone could potentially mean life or death. By talking on a cell phone a person might not pay attention to where they are walking and could possibly walk into traffic. It is just as dangerous as driving and talking. I say they should definitely be banned in order to save lives.
People are perfectly capable of using cell phones in crosswalks in completely appropriate ways. We do not need more nanny state laws telling us when we can or cannot use a cell phone, particularly when we are not driving. People, not laws, have to be responsible for their own safety.