Officially speaking you should not place your electronics (i.e. phone, tablet, memory card) on top of the system while it’s operating. The manufacturer is not responsible for any damages caused to your electronics for such cases.
Now in practice (and unofficially), as the magnetic field is so low (i.e. 45 µT – 120µT) is basically about the same strength of earth’s magnetic field, it simply has not enough field strength to cause any corruption or damages to your electronic devices.
However people with pacemaker should stay away from the system still, regardless.
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