Newsagent City

"Please note: Only 2 school children allowed in these premises at any one time" it says on the little black & white sign put up inside a newsagent's. "Aha - yes - what's that supposed to mean - schoolkids, do they steal? Aha, ok." is what I get whenever I point this out to non-Londoners. The speed at which this signage is being interpreted, learnt, accepted as part of the city is amazing.