In one of the bargain-binned dot com frenzy era books, I remember an AOL executive dismissively claiming that they (AOL) could put a AOL login or logout popup ad that said "Click here to pay $19.99 for absolutely nothing" and some fraction of a fraction of their customers would buy.
It cannot be ruled out that those kinds of ads won't ever come to Facebook. Ads that buy with one-click (despite Amazon's patent) and rely on partial user confusion and deception as a business model.
If Facebook did that, or even if advertisers did that and Facebook didn't kick them off, it will put the brand in serious trouble, they'll get fined, etc.
This is the sort of thing small scummy businesses do where the owner can hide behind it, go bankrupt and start again. It's not something a top company would do.
I am not saying big companies won't do evil things. This isn't going to be one of them.
And also you don't need to confuse people into paying for nothing. You can do it with their eyes wide open. In-game purchases, for example.
It cannot be ruled out that those kinds of ads won't ever come to Facebook. Ads that buy with one-click (despite Amazon's patent) and rely on partial user confusion and deception as a business model.