My answer is may be, but not before I can measure the shower stream if it had any lethal voltage leaking into it, and I mean anything over about 12v, the guy testing should have put one to a real test with meter probes measuring any currents in the shower stream to see what sort of lethal voltages were filtering through or past that earthing wire.
This reminds me of an immersion heater element that corroded completely exposing live and neutral directly into the tank, the water was only getting Luke warm, but thanks to eddy cage effect and the tank made of copper and earthed meant the occupants never received any shock. (this is well before time of the RCDs.
The first electric shower unit I saw, in the UK had element inside a plastic pipe carrying the water, so was not really very different to what is shown. I never got a shock form it so seems it worked. I would expect today it would trip the RCD, but the real problem seems to be poor quality build rather than heating design.
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