The first thing advertising has to do is catch one's attention. Being shocking or outrageous is certainly one way of doing that, although it's not always appropriate. Or welcome.
It's much more difficult to get a consumer to stop thumbing through a magazine and take the time to really look at your ad in a Rated G, family-friendly kind of way.
That's what makes these ads so great.
The images stop you in your tracks. They're funny, with just enough edge to be interesting. Even the wording of the offer is unexpected: grown ups travel free. Yet there's no uncomfortable explaining to do should your five-year-old catch a glimpse of the ad.