I don't see anything wrong with the ad campaign (I thought this was a really old thread, and didn't realize it had come to Canada until I finally clicked on it).
It uses the word "probably," it doesn't attack religion, and it tells people to stop worrying and enjoy life, which is a positive message. It's much better than a bus ad that says "There is probably a god, so start worrying and stop enjoying your life."
Also, I just don't care what's on a bus. I haven't had an atheist knock on my door to tell me there isn't a G-d. As long as they're not knocking on my door, asking for my money, or telling me I'm going to be punished for eternity, I don't care what people put on a bus.












