Mibs, I take your point and of course I agree with your premise that the claims made by religion (e.g. there is a god) cannot be tested by science and are therefore purely a belief or faith system. However, to keep on-topic I think that the next step in the argument - that because religion lies 'outside science' it is an invalid and incorrect way to view the world - should not be taught in an RE classroom, many children will believe that what they have been told by their family etc. is true and some will never change their views on this throughout their lives so it is important that they learn about the belief systems of other members of society. This is a pragmatic view of how to deal with the education of children about religion in the world that we live in: "Some believe this, others believe that, and there is no way to tell who, if anyone is correct, it is based purely on faith."
The fact that religion is not a valid scientific viewpoint SHOULD be taught though, in the science classroom, where the differentiation between believing something is true and actually being able to prove something is true, and the power of proof, is clearly conveyed. Maybe in this way seeds of reason may be sown in a few little minds.