From the Illinois Policy Institute:

More than 160 school districts in Illinois lock kids out of participating in school activities simply because they aren’t full-time public school students.
It’s not the law. The Illinois School Code allows school boards to make district activities inclusive for all resident students.
But those 165 districts completely exclude part-time students. A student could attend school five or more hours a day and still not get to compete with the marching band on Saturdays.
Some districts’ policies would be comical if they weren’t so unfair…
Even some districts that do allow part-time students to participate have unfeasible restrictions. Many require a half day of attendance or more.
Requirements for participation follow the name of the school district, if it has high school grades.
Johnsburg School District 12 – half day, excluding lunch
Alden-Hebron School District 19 – half day, excluding lunch
Harvard Comm. Unit School District 50 – prohibited
Marengo Comm. High School District 154 – homeschool only, athletic = no attendance requirement, non-athletic = 2 courses
Community High School District 155 – prohibited
McHenry High School District 156 – half day, excluding lunch
Richmond-Burton Comm. High School District 157 – half day, excluding lunch
Huntley Community School District 158 – half day, excluding lunch
Woodstock Comm. Unit School District 200 – half day, excluding lunch
Wauconda CUSD 118 – prohibited
Barrington CUSD 220 – no attendance requirement
Community Unit School District 300 – half day, excluding lunch
Other districts can be found in the link in this article.
