Once upon a time, a Scottish girl was living in New York City while attending college.  She lived in a fifth-floor walk-up with three other girls, one of whom was from Sioux City, Iowa.  The girls shared cooking responsibilities, and the girl from Iowa was famous for her loose meat sandwiches.  Now, the Scottish girl was horrified by the thought of eating something called "loose meat", thinking that it might escape its bun and attack her, but after one bite, she was hooked.
Fast forward 20-ish years.  Now the Scottish girl is a mom who is very health-conscious and wants to feed her kids only the best and most healthful foods.  But she is tired of hearing the complaints from the ingrates who want hamburgers all the time.  She remembers the magical loose-meat sandwiches and thinks, "Hm.  I'll bet I can adapt that recipe and make it not only way more healthy, but easy, too!"
And thus, slow-cooker Loose Meat Sandwiches are born.