Has this changed since they originally brought out the guidance? I kind of see the point if it's a completely separate area of the shop or on a different floor (eg in a large M&S it would make sense to keep the floor with the food hall open and close the other floors off)
However, if you are in a general supermarket with different aisles selling different things, it's silly , you are there anyway and people can dither buying a jar of jam, so stopping them buying a pair of socks won't stop the dithering!
Boots must be getting so excited about cordoning off the make-up again 