'Magnetized' is a notion i do not subscribe to. (aside from the usual magnetism stuff) Thus my stuff never gets 'magnetized' since no such thing exists in MY world view.
(Like it also does not need to be cleansed of evil demons. In some cultures this 'cleansing' is a requirement. )
If it does exist and I am unaware of it. then i also do not have to worry about it, as i never noticed any such thing anyway. and even if it indeed did sound better without being 'magnetized' since i never heard it that way, nor can I tell the difference, How can I miss it?
It is not the same sort of problem like "Gravity" where one can ignore it, but only at ones' peril!
So, no i do not concern myself with magnetization, nor would I, even if the outcome is truely dire. Like it sounds like it is an all Bose system.
Or even turning off digital stuff when listening to analog. i do not. I do not hear a difference, and so it does not matter for me.
Notice i do not say it is a lie. Or the person is nuts. As it may matter to to others with different equipment than mine. And someday i may notice a difference. at THAT point i will take action.
So I do not do anything about "magnetism" in my setup, nor do i give a rats' ass about it AT THIS TIME.
Though I agree for some folks it may pose a problem.
And along with turning my stuff off, suddenly i am stuck with a problem of bad sound. i think I have to just leave it on all the time, and my shrill bits of sound will vanish.
Just a guess, but it is a co-incidence hey? I am particulary fussy about the top third of the frequency band.