One-shot games end up with firms cheating on collusive agreement. Firms will always cheat in last period. In next to last period, firms know that each will cheat, therefore there are no costs to cheating in next to last period. The reasoning is true in every period since every period is the next to last period before cheating begins. Once an employee has decided to quit, the incentive to not shirk is removed.
Firms can respond by firing workers who submit a resignation.
Policy backfires since employees can react by not announcing their plan to quit until their last day. I traveling salesmen made exaggerated claims as to the quality of their products. Potential customers quickly learned that itinerant salesmen were not to be trusted. The essence of the game is that players choose at different times. Outcome depends on startegies Strategy 1 B decides to choose down if A chooses up and down if A choose down.