In reply to FrankBooth:
It's probably more to help them keep a visual check on their group numbers when they're out and about rather than any comment on the suitability of your son's coat.
But yes, they do seem to like to do things 'just so'. My two have just done it.
Apart from my daughter finding herself in the middle of a police incident on one of the local estates that involved the breaking down of doors, they enjoyed it thoroughly.