Could be an idea worth to try out.
But, those contacts are meant to be closed and then the machine turned on, I suppose. Which means that while there is still movement of the kettle w.r.t. its baseplate, there won't be any voltage present.
Also, during heating, there may be the odd movement of the kettle, but normally the kettle will remain undisturbed during heating, until the water boils.
Things are a bit different with windgennies, where there is constant movement of the slipring and brush while under power.
Also, it is 'consumer grade' stuff. I do have an opinion on that. In windmills, the best is not nearly good enough, IMO.
Good thinking though. Hope that I'm completely wrong with my above statements and that it will prove to be a useable solution for some windmills. Me too I'm still looking for a good source of cheap & useable sliprings. Don't hold your breath though...
Peter.