Some do. About 15 years ago I was doing a regular weekly commute and due to my size at the time, Southwest would ask me to purchase two seats. If the flight wa

Some do. About 15 years ago I was doing a regular weekly commute and due to my size at the time, Southwest would ask me to purchase two seats. If the flight was not full they would refund one ticket. Since Southwest uses first come first serve seating, you would get preboard status and a little card to place in the second seat. I was ok with that accommodation, it seemed reasonable and with a little research into the flights and how often they were truly full it was rare that i didn’t get a refund.