Free: Contests & Raffles.
Its got to be a mix of desparation and ignorance. I also feel that too many hunters have way too high of expectations that they should be able harvest limits eveeytime. Since thier goals are so high they get desperate to fill their bag - like skybusting. They're also likely to shoot before legal hours because they're only duck hunting to shoot as many ducks as possible. Just my belief based on my observations.
Just FYI: the term is "skybusting."