could be confusing

My mind works in odd ways at times (some would say most of the time) and I am often set thinking by signs.So many signs can be taken in different ways from what was intended - in the hospital was a door which said it was alarmed (what by?) and must be kept closed at all times (so not much use as a door).
I am always a bit bemused by this gadget so when using it today decided to blip it. Is it for shredding hands - but it depicts a "no hands" symbol?