I've just tried a depotted Trax on a magnet and there is
some attraction but not enough to hold the pan to the magnet upside down.
However, it's an electromagnet with an
alternating magnetic field (which is relevant because it causes
Eddy currents) and it's
incredibly strong. It's designed for erasing magnetic media (tapes and discs). It even attracts a pure aluminium rod.
I can't get the pan to attract to the magnetic adhesive sheet I use for depotting. I need to get myself a stronger fixed magnet to play around with and report back.
It is possible that M·A·C pans have changed in recent years from aluminium to stainless steel as the cost of aluminium has risen.
Update: I have just found a nice strong fixed magnet and it has no attraction whatsoever to the Trax pan. The attraction shown with the electromagnet is definitely due to Eddy currents. If newer M·A·C pans are attracted to fixed magnets it's because they've changed the material so there's no guarantee that all M·A·C pans will stick to a magnet when depotted.