I've read about various public transport commissions banning the atheist bus ad on the basis it might offend. In my opinion, the way the advert is stated is probably more truthful than the majority of adverts for women's shoes or men's colognes.

There is talk of talking this issue to court as a matter of free speech.

But here is the twist; imagine if all stated claims of 'truth' required substantiation by evidence. A sort of truth-in-advertising social contract out of respect for the public eyeball.