During especially tight economic times, the district does not want to pay for kids who don't live in the township.
Students jumping districts is a chronic problem for several districts adjacent to Philadelphia, but Upper Darby may see more than any other with teens taking public transportation from West Philadelphia presumably seeking a better school.
"It's just a wonderful place to be, rich curriculum, great atmosphere, rich diversity," Superintendent Louis Devlieger said.
To try to get a handle on district jumpers, Upper Darby had the families of all 3,600 high schoolers reregister, showing proof of residency. It was a big undertaking, but it uncovered several hundred suspected illegal students.
"We have had 7 disenrolled through due process hearings and we are looking at another 300 to face those due process hearings," Devlieger said.
In addition, 122 have already withdrawn on their own.
The overall savings could be as high as $3-million.
Some parents we spoke with say they understand why adults would try to sneak their kids across city lines, but they also understand the crackdown.
The superintendant says the process of identifying district jumpers is very complex, but Upper Darby is committed to making sure those who are enrolled at the high school really do belong here.