> Even assuming that there isn't already some precedent that a checkbox allows them to use your uploaded likeness in whatever they want, is your premise here that you have more time and money to spend in a legal battle with Facebook or Google?
There's currently a class-action lawsuit in progress against Facebook's use of facial tagging of Illinois residents: http://www.chicagotribune.com/business/ct-biz-facebook-taggi....
Regardless of how deep Facebook's pockets are, I could see another class-action lawsuit taking them on over recruiting its users into becoming uncompensated spokesmen in deepfake ads hocking products to their friends.
Also the legal situation in other jurisdictions may be less friendly to Facebook's usage of this technology, to the point where their deep pockets won't help them. I'm no international lawyer but I think that's definitely a possibility.