This is another lingering instruction by airlines. In washrooms we see a slot for shaving razors. Unfortunately, such sharp objects are no longer permitted on board. So I wonder how long it will be before this feature will disappear or be patched-up in some way.
This photo of a sharps receptacle was taken on one of my recent flights. Strangely enough, I do not understand how hypodermic needles can be permitted on board. Of course, they are used for medical purposes by diabetics. Yet, they could contain any serum, including contaminated blood. Would such a device not be a powerful weapon on board? If a madman says that he has a contagious disease inside his syringe, would a pilot want to risk contaminating everyone on board?