children traveling alone

Children in the late 1800s and early 1900s often worked, and also traveled alone. My great-grandmother from Ireland traveled as a 9 year old accompanied by her 12 year old cousin to meet relatives here. Children over 12 who did not pass inspection were sent back to Europe on their own, children under twelve were accompanied by one parent. How desperate must people have been to scrape up enough money to send their children alone across the Atlantic to a new country knowing that they may never see them again.