In today's world of everyone believing that they are entitled to special treatment for one reason or another, it's increasingly difficult to be a Human Resource/Human Capital professional (I hate these terms) or labor lawyer.
Let's take a look at the UK in particular, where the rising issue of workplace duties and religious practices appear to be increasingly at loggerheads.
The primary issue here is not the fact that people don't want to do things that they believe are forbidden by their faith. The primary concern is the fact that government authorities have provided little if any guidance or roadmap in dealing with such cases. As a result, companies and lawyers are hesitant to create jurisprudence or fall on the wrong side of the issue.
Of course, it's not entirely the justice system's fault. The fact of the matter is that these cases are still relatively new as matters of law. As a result, very few cases have been heard on appeal, so there are very few legal references to use when arguing one's case.
This is still a dangerous territory for companies to tread as the issues often pit one person's personal beliefs against the norms of the company (and thus co-workers).
While certainly needing to be respectful of their employees' wishes, it would also help for those making claims on behalf of their beliefs keep in mind that not everyone else in the company may share those beliefs and their rights, in turn, are infringed when you must be accommodated.