The Job card that I had for cleaning the flight deck stated that aircraft electrical power be removed first.... therefore, if a switch is bumped of changed, nothing will happen. If a cleaner were then allowed to carry out the cleaning, we would then have to inspect the panels for correct conditions before applying power again.
That's why this job is left to engineering.
Also, personally, I remove some of the control knobs and panels for access to clean properly.... a job that is not really in the scope of a cleaner.