Holy Cow.
I have a friend who has had to leave work and make arrangements because her daughter is so out of control at school. She's also out of control at home, so it's an obvious pattern. Nothing new.
Don't laugh, I've been home with pneumonia, but I watched a Dr. Phil show about out of control kids. I believe he said that statistics show that 85% of little kids who get sent home or are in trouble all the time at school end up in Juvenille Hall. Parents feel guilty for working or not giving their kids enough and as a result, they don't discipline their kids. They also don't want anyone else disciplining them either. So....as a parent, if no one has a grip on a 4, 5, or 6 year old, who is going to have a grip on them when they are 14, 15 or 16?
I don't think you should be mad at the school. I think you should talk to them because the "thinking plan" thing obviously isn't working. Losing recess isn't working. You thinking that they are being unfair to your child isn't working.
Your daughter is 6, not 3. She is not a toddler. She is in the first grade. Give her some credit. She is well capable of understanding behavior that is expected of her and what the consequences will be if she chooses not to behave in the expected manner. She's old enough to understand that if she can't get along with certain kids, she can happily play away from them because they aren't worth losing her own recess over.
Cause and effect.
Choices and consequences.
I'm 49. I was raised old school. If I had to sit with the principal because I wasn't behaving at school? OMG. That would be nothing compared to the talk in the car when my parents picked me up.
That NEVER happened, by the way.
I raised two kids as a single, full-time working mother. We all had our jobs to do. Mine was going to work and theirs was going to school, doing their work, following the rules, having manners that I so staunchly taught them at home.
I mean no offense to you in any way, shape, or form, but seriously....the school seems to be trying to help your daughter understand a concept that all children, as well as adults, have to understand. You have to behave yourself in social situations. Like it, hate it, it doesn't really matter. You still have to do it.
If you're not enforcing this at home, you're not doing your child any favors.
Again, just my opinion.