As long as it is accessible and useful, it will be used. Organized crime is around despite it being illegal. Considering how lucrative tracking people is, people will do it illegally. Even corporations as long as penalties aren't significant enough. We really need a three strikes law for corporations. Three egregious intentional violations and corp, is dissolved all assets going to support the needy.

"things should be legal because some people will do it anyways" is not a very compelling argument. I'm sure I don't need to explain to you why extrapolating this line of though to, for example, murder is silly and not worth taking serious.

Love the last bit. Lack of accountability for corporations is a problem. That plus stiff penalties for executives or individuals using facial recognition without consent should put a stop to it pretty quickly.