The article doesn't specifically mention iButton or one-wire systems. It just describes a metal plate "to hold a magnet next to" that's connected to a fleet tracking system for driver identification. While this is similar to how iButton/one-wire systems work, it's not fact since the article doesn't confirm the specific technology used.
I have one of those buttons and readers from a project kit from a long time ago, and it's not magnetic.
I think the magnet reference is just a misleading mixup on the dealers side who was probably not familiar with iButton specifically. Very old immobiliser systems used simple reed switches and magnets - basically just pure security by obscurity.
The purpose of the switch is also unconfirmed by the article, but this exact combination of cheap chinese button + ibutton reader were an extremly common retrofit into Opels in Hungary.
I have one of those buttons and readers from a project kit from a long time ago, and it's not magnetic.