Investor scams are unfortunately rather common.
As soon as secrecy, a breakthrough and a very large market coincide the gullible and their money are soon parted. I personally don't think this is a bad thing because it keeps me employed, at the same time you'd wish that this sort of thing would stop because it most likely hinders genuine breakthroughs from being given the attention they deserve. Some of those get recycled a few years or decades later so not all is lost but still, a few cold fusions and AI winters and the tech industry as a whole suffers.
As for the uBeam, ultrasound is a strange medium to choose for this particular job, ultrasound is fickle, has a ton of side effects, isn't particularly efficient and interferes with living creatures in all kinds of un-desirable ways. Going the electromagnetic route would seem to be the first thing to try (and some companies are doing this and have products, maybe not 'miracle class' but they'll do the job they're designed to).
The best bet for getting rid of the charger cord are a strong reduction in required power for the phones, better battery technology, maybe micro fuel cells or some other exotic conversion technology.
Populating the world with ultrasonic transmitters with about the same range as the charge cord they replace seems to fix one minor inconvenience by replacing it with a much larger one, not a company I'd bet on.
Or, and this is really out there, larger batteries?
Which elfin focus group told everyone that a phone's weight should be measured in carats? I'd sacrifice a few extra ounces for a doubling in battery life without adding new devices.
Of course anyone can go blow their money at a casino and with a much lower odds of return than investing on AngelList, so I'm not sure it's an overall bad thing. Still I am concerned about loss of signal in noise and about 'winters' as you say.
Crowdfunding is currently doing a great job educating people on the risks of putting money up for vapourware but since those are not investments per se there is still a gap in that education that will surely be filled once the stops are pulled. Organized crime is already involved in investments, look no further than the LPs of some of the funds that have high visibility. That's a far quicker way to get a return than to bilk a few million out of the pockets of the gullible public at large.
Also, a common trajectory is shooting for something impossible, but discovering possible and useful things along the way which turn into great businesses. So even if you're 100% sure the idea is impossible, it might still be a good investment.
I don't understand how people can raise money like this. Investors usually like to actually see evidence that you are actually doing something, right? Right?