I did not know that. But it reeks so much of corpo team building I would not be surprised in the least. Do they do that out on the street, though? My first thought when I saw this was "oh, that must be the hazing for the new recruits! How amusing!"
It was not. It was a daily thing.

I dunno exactly what they sang, but yeah, they would absolutely sing something at the beginning of the day, lined up on the pavement outside their office, with the manager directing like some sort of corpo choral. I guess it's one of those team building things...