For the last few months the School Department has put the kibosh on retirees being able to register to substitute teach. Why? People who retire and get a public pension are limited in the number of hours and dollars they can earn as a retiree, should they wish to return to the public sector. Retirees are obligated to know this information, the limitations, and to repay any overage, should that overage occur.
The School Department was worried that it would get burnt in this process, although the law is clear and long-standing: the retiree himself or herself is responsible for any overage. It is worried no longer. So, long story short, retirees are now free to substitute teach subject to the limitations. A description of the limitations can be found here.