Of course a magnetic field creates electric current, Physics 101. Just like current creates a magnetic field, especially in wires in loops.
I would love to see someone actually measure sound (which is what we can agree on here is what matters) with and without the SGs in a room at different listening positions with and without the devices just like when you prep a room for acoustic treatments.
I would bet it is not measurable, especially since the main proponents are saying it doesn't matter where they are placed.
Some things are measurable and not audible, but not the other way around.
It probably has some effect on some people who can then become better focused on the tremendous detail in the sound. Those people may be more relaxed. It shows up in health articles that ARE scientific as being potentially beneficial.
Please someone who has the SGs and sound measurement equipment put this argument to bed (if that is possible). I doubt it will change anyone's opinion on whether to use them or not, but it would be nice to at least prove what you are hearing is actually out there.