By Jamie Gumbrecht, CNN
(CNN) - Seniors at Kenowa Hills High School in western Michigan thought a mass bike ride to school was a sweet sendoff for the last day. Police escorted the ride and parents lined the route. The Walker, Michigan, mayor brought doughnuts.
But principal Katharine Pennington didn't know. She said the ride was dangerous, tied up traffic and prevented staff from making it to school, CNN affiliate WOOD-TV reported.
She sent more than 60 students home after the bike ride yesterday. Soon-to-be graduates were banned from participating in the senior walk - a traditional final walk through the school's hallways - and some were told they wouldn't be allowed to walk at graduation, a decision that was later reversed. Students told CNN today the senior walk was rescheduled, too.
Pennington released an apology on Wednesday, along with the superintendent, after parents and students flooded a school board work session with complaints.
“Yesterday, I made a mistake and sincerely regret my actions. Did I overreact? In retrospect, of course I did," Pennington's statement said. "I apologize to the students, their parents, and the community for a reaction that blew this incident out of proportion and called into question the character of our students. Our senior class has demonstrated leadership, unity and school pride throughout this school year. My actions and emotion overshadowed what should have been a very positive senior activity. I have learned much from this experience and do not consider myself infallible.
“I now applaud the students for their foresight in contacting the police department to ensure the safety of their senior surprise. I only wish the police department or others who may have known about this would have let us in on the surprise but, of course, it wouldn’t have been a surprise had we known in advance."
The school has a zero-tolerance policy for senior pranks, students and parents told CNN.
"She had absolutely no clue, but, I mean, that was the whole point of it," Kenowa Hills senior Cody Nicks told CNN. "It wasn't even a prank, but a celebration for our last day ... The way it was reacted to was completely absurd."
The principal's response to the ride, which was held during National Bike Month, sparked protests among parents and students. So many packed a school board work session Tuesday night that they moved the meeting to a middle school auditorium, WOOD-TV reported.
A police officer who knew about the bike ride, but did not inform superiors, also will be subject to an internal investigation, WOOD-TV reported.
"Most of us senior parents did know about it. We found it harmless," Cody's mom, Rachel Nicks, said. "They wore bright colors, police escort ... I don't know how much safer it would have been if they would have notified the administrator."
Share in the comments: What were your senior pranks, and how did your parents, teachers and school administrators respond?