> Figure out which part of the rack points north, stick a really strong magnet there.
Such a strong magnet can be detected, too, e.g. with four 3-axis compasses.
> Also, spoof the GPS signal to avoid your next attack, wrap you in a faraday cage and broadcast an identical set of WiFi/Cellular signals.
Nice idea, but in case you're using a cellular uplink, as soon as the faraday cage is in place, your trigger fires. Also, spoofing GPS signals requires expensive equipment and IIRC also cooperation of the Feds.
> My point isn't that any of this is more or less practical, simply that any protection you can dream up can be defeated if they know about it and are expecting it.
Which is why you don't publish every detail of how your farm is protected ;)