NCAA season ends. Coach decides he wants school to swim as school club all year long. Can do so, so long as he uses swimmers currently eligible to swim for his school at all times. Cannot use swimmers whose school eligibility terminated at the end of school term. NCAA season ends.
School wishes to compete as school club to end of term.
Coach decides to use one of his red-shirted swimmers on team. It doesn't change the conclusions above. He can swim unattached in open USS competition anywhere he likes during the whole of the school season without regard to the 120-day rule. Once the school season is over, he can swim for any USS club of his choice without regard to the 120-day rule. But once he begins to play around with swimming for any USS club, other than his school club, during the school season, he then must comply with the 120-day rule.