Yes, the school district has gone too far. The school does not have the authority to punish or discipline parents with detention.
Not that any of my children would have excessive tardy's... but if a school tried to tell me that I had to "stay after" because of something my child did - I would tell them NO! And while you're at it, why don't you find yourself a good lawyer because I'll be taking you to court now :) And be sure to pretty yourself up because mamma is going to be calling every news crew in the state to come investigate your school and how things are run.
That's just craziness!
Yeah, I understand there are some parents out there that just shouldn't be parents... just like there are parents out there working shifts at their jobs that would not allow such nonsense as "staying after school" - these parents are working hard to pay the bills & keep little Johnny dressed, fed, and supplied for all of the things the school demand he supply for himself; things that used to be provided back when we went to school. Yet somehow, now, they just can't afford it.... hmmmm interesting.