Laura Bauer had a good article this weekend about churches and how they try to accommodate registered sex offenders -- while also protecting other members of the congregation, especially kids. As Laura notes, most RSOs are required to avoid contact with young people. In a few cases, that's meant they couldn't attend the church of their choice.
FindLaw has a roundup of cases where this issue has come up. And this Time piece is interesting -- I thought it made an interesting point about why sex-offender rules should apply to churches, too.
The premise of the law is sound, says Laurence Tribe, a constitutional-law expert at Harvard. "If the moment you enter a church you don a cloak of immunity from the rule of law, then churches would become sanctuaries for crime," says Tribe.