“There’s Probably No God” What triggered these ads on the buses?

OC Transpo officials previously decided not to allow the ads, which read: "There's probably no God, now stop worrying and enjoy your life”. But on March 11th 2009 Ottawa city council, after seeking legal advice, has approved a motion that will allow billboard ads to appear on the city's buses that question the existence of God.
Apparently, the campaign was triggered on June 19th 2008 when a Guardian reporter/comedy writer, Ariane Sherine was walking to work and saw ads on two buses "When the son of man comes, will he find faith on the earth?" (Luke 18:8) followed by the web address: http://www.jesussaid.org/ . Ariane was particularly offended by a message on the web site which warned anyone who doesn't accept the word of Jesus: "You will be condemned to everlasting separation from God and then you spend all eternity in torment in hell (Matthew 25:41). She then called the Advertising Standards Authority to complain and was told that the quotations used are clearly from the Bible and there's nothing in the advertising standards code to prohibit advertising a religious message. Then she questioned another unrelated ad by Carlsberg that said that their lager was "probably the best lager in the world”. Further investigation revealed that Carlsberg used the word “probably” to prevent jealous rivals calling in the lawyers and adds a touch of modesty to what is otherwise a simple, big, untrue – and effective – boast.
Ariane was supported in her campaign by leading secularists who jumped on board to help raise the money and after a six-week fundraising effort in which nearly 1,000 people pledged money to counter what they said was an unfair pro-religion bias in the advertising world. The initial goal was to raise £11,000 to fund two sets of atheist adverts on 30 London buses for four weeks. However, with the help of the British Humanist Association (BHA) and the prominent atheist Professor Richard Dawkins, the campaign raised £135,000 Given this unexpected amount, Ariane announced on January 6, 2009 that “800 buses – instead of the 30 we were initially aiming for – are now rolling out across the UK with the slogan, "There's probably no God. Now stop worrying and enjoy your life", in locations all over England, Scotland and Wales, including Manchester, Edinburgh, Glasgow, York, Cardiff, Devon, Leeds, Bristol and Aberdeen”. This campaign has now moved to the international arena and its effectiveness seems to be linked to the word “probably” which makes people think!
The Toronto Transit Commission approved the advertisements on the commission's buses, trams, and metro and rapid transit trains. Following a request by the Association humaniste du Québec, the Société des transports de Montréal, Canada, accepted the proposed message "Dieu n'existe probablement pas, alors cessez de vous inquiéter et profitez de la vie" (a translation of the original UK advert) and the bus should take the road during March 2009. Secular Humanists and Free Thinkers in Halifax and London and have had their adverts refused, while religious group have previously advertised in those cities. In British Columbia, Vancouver, Victoria and Kelowna adverts were barred on the ground that no religious advertisement is allowed on buses.
The ads are likely to offend many believers, especially some of the elderly as they are preparing for their final journey, as well as will confuse some young people about this delicate topic. For this reason it would make sense to bar these ads on the buses.