With the association or commissioner assigning the crews, it gets into an employee-employer relationship. The official is told with whom and when to work.
We are independent contractors and cannot be under such restrictions without the Assn. or Commr. being liable for taxes, workers comp., etc. Someday your state dept. of revenue will come calling about it, as the state of Oregon is now.
My former Oregon assn. assigned individuals to each game. We'd work with different people each week. I liked this system because you'd learn something new from different experience levels and it created a lot of camaraderie.
In Illinois, we form our own crew and accept assignments as we wish. Last season we worked for six different assignors, but we are isolated because we don't have a chance to see other officials and such. Nor do the majority belong to an association.
Dump those losers, Rut, and come work with me!! I'll even buy a "Les Miles, More Wins!" t-shirt.