There are chips that allow you to gather and store miniscule amounts of electricity from surrounding RF radiation. Bluetooth LE is also designed to be a very low-power devices, so it is within the realm of possibility for this particular project.
[1] http://gnodevel.ugent.be/crr.ugent.be/archives/1628
[2] http://en.wikipedia.org/wiki/Bluetooth_low_energy#Technical_...
I think the product is very much possible with current tech. I can't tell if the creators know how to do it and just used less technical language or if they have no idea what they're doing. At any rate, there have been way crazier scams on Kickstarter (raman spectroscopy tells me nutrition info etc).
Didn't Kickstarter ban showing mock up or rendered hardware as substitution for the real thing? Maybe that's all this is?
However, there's no way you'd get even 100 uA by harvesting RF energy in a package that small.