Are you insane? A Faraday cage protects against magnetic fields and other interferences, thats why they exists, the earths magnetic field is no problem btw, its actually protecting our shit because ot keeps most of the magnetic Solarstroms away from our electronics.
It was also just a fun fact type of info, as its impractical, the data may be there but access will be lost in the near future, that was what i said as well. I suggest microfilm or vinyl. Nobody is going to take care of the stuff after you die anyway.
(btw you could pay say AWS to keep your archive forever, as long as Amazon exists it will be ported and always accessible, paying after your death would be a problem however...)