In my first job, I once asked a customer if he'd like the documents couriered to him, or sent by ordinary post? He asked what the difference was, and I told him that by ordinary post, well, "You know how unreliable it can be". He said, "Well, as I'm in charge of the mail distribution centre for the western sector of the metropolitan area, yes, I have a fair idea". Fortunately, he accompanied the comment with genuine amusement and laughter. How stupid was I? His occupation and employer were written on the documents I was sending!
FWIW, he got them couriered.