In many situations I'd agree, but once they're up it's too late - people at risk may have seen them.

Again ... they've warmed their target market up with this sort of prequel to the campaign.

The marketers will be loving all the free publicity of all the MySpaces et al ...

I don't think seeing those images should be forced down people's throats, and if they're hanging all around a city, that's what they are.