Windows Phone Thoughts: Location-based Advertisements Sent to Your Cellphone?

"French-based (but multinational) advertising delivery experts JCDecaux is about to unleash an interesting advertising scheme based on sending highly targeted ads to your cellphone as you walk by a billboard or a bus stop. An initial trial will happen in France first, with plans already in place to expand the reach considerably. The idea has some potential, and something like this may soon be inevitable, but there are a few problems with it too, such as invasion of privacy."

I can think of a lot of colorful adjectives to describe this idea, but I'm pretty sure that "interesting" would not be one of them. Now, to the credit of the "inventor," his vision is that each person would have to consent to this service before receiving the ads (in exchange for free ring tones or something similar). Of course, that leads me to wonder how often I might get prompted to participate. If I'm to get prompted everytime I step out of my house, I'd have a really hard time imagining this idea going far without a firestorm of protest. What are your thoughts? Do you think this idea will fly?