The implication of what you're saying is that it's impossible to defraud an investor because the investor is always going to be partly to blame for not doing enough work to prove a business they're putting money in to isn't scamming them.
To an extent I actually agree, but I don't think that should preclude an investor from suing. If a business went to extraordinary lengths to fake some working tech then I think it's fair for the investor to get their money back, and it should be up to a court to decide whether or not that happened and what 'extraordinary lengths' means in any given case.
Yes, an investor is always partly to blame if they get scammed.
It's fair for them to sue but I think the court will ask them why they didn't do any independent verification of the technology to make sure it actually worked. That's pretty much the bar for anything that's labeled 'revolutionary' or that you perceive to be 'too good to be true'.
If it were a much more normal product with proven tech then I'd be more inclined to let them get away with 'belief', but in this case (and uBeam, to name another) you really want to see the technology for yourself and you want to verify that it works.
Short of stage magic they shouldn't be able to get away with this.
One of the most interesting DD's I ever did was a company that tried to rig a demo, they didn't get away with it because I went in assuming it was a rigged demo and I figured out how they did it. What makes it interesting is that today what was 'magic' in the 80's is actually quite normal... But back then you'd have to be doing something quite impossible with the technology available in the day to be able to give that demo unless you rigged it.
To an extent I actually agree, but I don't think that should preclude an investor from suing. If a business went to extraordinary lengths to fake some working tech then I think it's fair for the investor to get their money back, and it should be up to a court to decide whether or not that happened and what 'extraordinary lengths' means in any given case.