They welcome kids aged between 8 and 17, but typically they are 9-14 (if there are older kids, they usually get the opportunity to become "junior counsellors", with a bit of responsibility and a few privileges)

Most kids don't explicitly get the metaphor for god - the unicorn thing distracts them. But I like to think it does teach them that arguing for the sake of arguing - or "being right" is often fruitless.

You make an interesting point about Dawkins. I recently had the fortune of seeing him give a talk and also managed to talk to him for a few minutes (whoo hoo! fulfilled my life's dream right there...). Granted, his talk was to a bunch of atheists, but he came across as articulate and extremely funny. Plus, he's a great listener (especially when confronted by insane rambling fans - tee hee)

The times I have seen him debate in mixed company (for example, on "The Big Questions" on BBC1) he made his points without attacking anyone, and presented himself in a calm and dignified manner.

I suspect he would like to use more subtlety, but is fully aware that it just doesn't get through to some people.

The only time I had seen him really lose it is on "The root of all evil?" - a face off with Teg Haggard. Makes compulsive viewing though