It's a lovely gesture, and an important sign of solidarity; however, it'a merely that, just a gesture. I hope that SV and the tech industry leverages its wealth and technical legal capabilities to fight these sorts of actions in court, unlike their responses to privacy intrusions by the federal government, British intelligence, and other foreign groups.
Over 1000 people, some of them very prominent, have pledged to quit their jobs if they are asked to do unethical things. How is that "merely a gesture"?
That being said, who is to say that it would be those people who were asked to do it? Most unlikely. It'd be the grey people, those you don't even know about. Those already doing it.
And finally, it's already done, isn't it? Facebook, Google, et al. I've worked for small companies before that are able to identify demographics of users right down to their likes, dislikes, and ages, even without submitting that information.
You think there isn't already swathes of Island-centric data out there?