Many companies don’t want the risk of employees causing disruption, social disruption, subterfuge… I recommend every company to pay out the 2 weeks every time, unless there is a serious firable offense. Even then, consider paying the 2 weeks. This creates good will and a likelihood that employees give 2 weeks notice. However, younger people seldom give 2 weeks notice. Some do.

Especially in the case of someone that quit, as others have pointed out, you have opened up the potential of increasing your unemployment insurance costs. Even an employee that left for another job, if they end up unemployed soon costs your company unemployment money ( depends on the state, but your risk can extend for 2 years). If you paid the employee through Friday, when they quit, you do not have this potential issue. You can still pay through Friday and avoid the potential issue.