Is いらっしゃいませ only used by staff, or is it used in other circumstances?
When I was at a dinner at a restaurant being held after a programmers' meetup, I thought that I heard it being used by one of the people eating (it could have been the organizer of the dinner for all I know) to welcome a late-comer. Or is it more likely I mis-heard them merely saying いらっしゃい or some other form of the verb?