yasmin,
I think if you really want to analyze it, my guess is that having the young children be witnessing the most "obscene" shot is probably more satirical than overtly dirty. I mean, the whole concept of having the woman in a glass box on display in skimpy attire while various people walk by and gawk is, I think, a statement in and of itself. Then when you consider that the most sexual pose is reserved for the youngest witnesses, I think it's a reference to sex being sold and flaunted to younger and younger audiences these days.
I just don't think the ad is meant to be taken as Gisele trying to be sexy. It seems like it's criticizing her objectification. But then again, even if I'm reading into it too much and it is just supposed to be her nearly naked and nothing more, like I said before, I've seen much worse.