1) If other people want to write contracts with each other that obligate them to do things for each other in response to bit patterns generated by my computer, that's none of my business.
Legally, you might get Tortious Interference pass the laugh test, but who is interfering? The author (if they're cautious) isn't running it, so you're likely looking at RIAA-style fishing for IP addresses for random people who installed the plugin and contributed a tiny amount, and we've seen that show already[1].
2) It could. Things have hard-to-predict effects. I see no reason why I should weight small startups as more important than the set of everyone disgusted by the invasion of every metaphorical orifice with surveillance tentacles.
3) Good on ya.
I don't know if I'm going to run this plugin or not. But this is exactly the sort of thing needed to level the playing field between the commercial surveillance shops (Facebook, Google, the other ad shops, on down the spectrum to phishers and other outright criminals) and actual humans.
We know that any form of legal or illegal online surveillance that has a chance of being commercially self-sustaining will be at least trialed. This has been demonstrated repeatedly. Legally, this is difficult to address sensibly because of the mismatch between the legal system speed and the tech-landscape speed (not to mention the inevitable unintended-consequence shakeouts, and the slowness of general wisdom in times of change). And that's even if assuming the Powers that Be want to address them, which is unlikely in the U.S. while a con-artist setting the agenda.
So that leaves making as much of the surveillance business model untenable as possible. I don't know what the right approach is, but it will likely be one that involves feeding the watchers lies.
I really don't like pissing on other people's work. But if that work is dedicated to things that make my life worse, I retain a right to, among other things, lie to their creation out of self-defense. It is that simple.
Random, related aside: I'm unlikely to have time to make this happen, but one thing I've thought would be fun is to see about how tricky it would be to repurpose some test equipment to be, say, a whole herd of Bluetooth phones[2] taking a walk by those iBeacons. Being more subtle would likely be a lot more fun, depending on the target, and would serve as a useful reminder of what 'unlicensed spectrum' means.
[1] Spoiler, here's the ending: https://popehat.com/2016/12/16/the-prenda-saga-goes-criminal...
[2] What's the collective noun for phones?