I think user talks about occasions where users sell their whole team out and start playing with their youth teams, to make a brand new start.
I dont see the reason though, why should this feature be implemented. It will require extra admin and Crew workload for something of not great necessity.
After all, all users want extra earnings, and being in the highest division possible will be to their advantage. If I was going to sell out, I would want to be relegated in the lowest division, I would want to stay where I am and get the highest income possible!