Eight Jacobs High School students caught horsing around last week on a homemade Slip 'N Slide as a senior prank must write a letter to school administrators promising to behave at graduation.
Only then will school officials determine whether they get to walk with the rest of their class Saturday, said Allison Strupeck, a spokeswoman for Community Unit District 300.
"With several thousand people expected to attend graduation ceremonies, there must be an assurance of safe conditions," Strupeck said Tuesday via email.
The Algonquin school has not determined who was behind the prank, which involved several students sliding on a tarp they coated with baby oil, water and liquid soap.
Other students slid in the hallway itself while their peers cheered them on.
The eight students were caught participating in the prank, but there is no evidence they were behind it, Strupeck said.
"If they had organized and perpetuated the hazardous conditions of last week's senior prank, they most certainly would have faced losing the privilege of walking at graduation," Strupeck said, adding that the investigation is now closed.
Nobody was injured in the prank, the school was on a brief lockdown while the mess was cleaned up, and police were called.
Jacobs officials met individually with the students and their parents Monday.
It was then that administrators decided the students should first write a letter promising to behave at graduation before the school decides to let them walk.
Senior pranks are allowed at Jacobs as long as they are safe and the administration knows about them beforehand, Strupeck said.
A similar prank a few years ago resulted in one student breaking a leg and another breaking a tooth, Strupeck said.
"While it is easy to discount a senior prank as simply 'kids being kids,' parents are counting on the school to be a place where their children will not get hurt," Strupeck said.