Good painters take them off the wall and then paint them, if you want them painted, the same color as the wall.

You never paint removable things in place. You always take them off so that you can (a) paint the whole wall even under the plate and (b) if the removable thing is getting painted, do a nice job on it separately.

LOL at the landlord special photos; my grad school rental had duct table and push pins in the wall that had been painted over. Of course the windows were painted shut.

absolutely no way they should paint over things- they should always remove the hardware, paint, then when dry replace the hardware.

Yes.

If they paint over switchplate covers that have to be removed later, you will have to cut around them and risk messing up the paint.