What is "cattle call seating policy"?

Other answers already have connected to the practice of some airlines of not assigning seats but just calling groups of passengers (or sometimes everyone) to join and grab whatever seats are available.

The phrase "cattle call" actually comes from the theater world, where it referred to open auditions, although sources differ whether the usage was started by actors feeling disrespected by the process, or by producers and directors disgusted with the stampede of ambitious actors.

But "cattle call" originated with 19th-Century ranchers and cow-hands, who would literally call out chants ("Co-bessie, co-bessie, co-bessie!" and "Co-wenchie, co-wenchie, co-wenchie" were popular, "co" meaning "come") to summon cattle to feed.

Cows are surprisingly easy to train in this way. A rancher friend of mine was in the habit of riding his motorcycle around his land and throwing cubes of alfalfa to his cattle. Soon, anyone on a motorcycle would find himself thronged by copiously drooling cows.