50 Billion a year stolen

I wonder how this jives with workers doing things other than work while on the clock?
Fortune says fantasy football may cost employers 13.4 billion a season. Then you ahve stuff like online shopping, and saintsreport to deal with.
Study: Fantasy football costs businesses $13.4 billion a season | Fortune.com

My employer is super nervous about people working off the clock and very quick to write people up/terminate them for doing so. Usually if someone is working off the clock here, its not management telling them to do it, its something they are just doing and not logging.