[allan87]

The read-only sensor isn't physically connected on the Pi circuit board, so the switch/lock on the SD card has no effect whatsoever.
If your SD card becomes read-only, that would be because the fileystem is corrupted in some way and needs to be fscked.

...Keeping in mind that the SYSTEM partition is supposed to be read only, and if the STORAGE partition was read only, he could not have copied a file to it (as he did).