Suggestion of Physical Precautions

[927589452]

You could move the USB ports to different sites of the device,
to make it harder to mistake USB keys
Add a optical barrier between the data ports on the dirty side to protect against USB killers

[Rafiot]

The protection against USB killer is easy: buying a new rpi :) It will be cheaper than doing any hardware change.

I'm not sure what you mean by "moving the USB port"? plugging an extension cable?

[927589452]

Yeah that was my Idea, one "Protected" USB extension with opto coupling and one normal to opposite sites