4. Treatment of children
This is a weird fact that will terrify modern parents: in the U.S. in the 1910s, you could send children via mail. In those years, the mail law made the lives of farmers easier, so they could send chickens via mail. But some citizens decided to use this law and started sending their children to their relatives.
It cost less than a dollar and the cargo was delivered right to the doorstep. This was much easier and cheaper than sending a child by train. It took until 1920 to make this illegal.