G day workers and folks answering phones/cutting deals can certainly detract from the effectiveness of CC, but how much ? Overtime costs money, G day pay costs money, shuffling schedules and delays costs money, and positioning people costs money. Off station reserve costs money and FTL clocks tick. Defensive reserve runs FTLs and if someone is used burns more hours as well as often overtime which is expensive. Shuffle and delays also start to induce FTL problems. Many are in overtime even without formal CC. High time flyers will time out by FTLs and have to sit. As long as there remains a strong baseline coalition I think it will be effective. If we were dramatically overmanned things might be different but we're not. Folks cheating might extend the time necessary to stay in CC but the loss of productivity will still be there. One never gets something for nothing.
Thanks and Cheers