Not with modern hardware. The operating system probes the bus to work out what devices are there. So configuration is dynamic (at least at boot time but potentially in real time). Maintaining and working with a config file is more trouble than it’s worth (and obviously in order to read a config file from a disk the operating system has already found a disk on a bus without the benefit of a config file!).
If you are operating the switch after the phone has booted then I suppose it could remember what was there. You already have an answer from an actual developer though.
I suppose maybe the status line could carry a rectangle with a question mark in it (representing “unknown”) when the switch is detected as “on” but a card hasn’t appeared and, once an actual card appears, an appropriate icon for the card replaces that “unknown” icon.
This all gets messy though because it has to work properly as part of booting (no kill switch state transition) as well as when a kill switch is operated after booting.