EFF is on the wrong side of this, just as they were on the wrong side of the debates about what to do about spam email back in the day. They're committed to the view that the only acceptable place to block any flow of information (which they define very broadly) is at the receiving user's end and that the end user must personally opt-in. This is completely at odds with the last 30 years of experience on the internet and shows that they've learned very little about how bad actors will abuse systems of that sort and degrade the experience for everyone else.
Depends entirely on what you mean by "prove". If you mean "explain or understand how physical processes give rise to conscious experience" or "from third-person observation, know with any kind of certainty whether a given system is conscious" - you run into what philosophers call the "explanatory gap" and/or the "hard problem". See https://en.wikipedia.org/wiki/Hard_problem_of_consciousness