Grounded at 5 years old?

At 3:30 today I received a phone call from Butteview. They wanted to know if Belle was supposed to ride the bus home, because she had told Mrs Montgomery that Becky (the sitter) was picking her up at the school today. They werent sure if they should keep her off the bus, because they didnt have a note from me saying to do this. So they called. I hadnt heard anything from Becky so I told them to put her on the bus. After this phone call I decided I needed to put a stop to the bus problems. I wondered if I should be extreme and ground her. But what exactly will I ground her from? Polly Pockets? Barbies? What kind of chores can a 5 year old do that she will HATE!? I just dont know. Then around 4:00 I get the following email:

Emmy: Belle asked me to email you, because she got in trouble in the lunchroom today. Another student had some toys in his pocket during lunch and he kept showing them to her. She told him she didn't want to see them. Anyway to make a long story short, Belle threw applesauce at him. The cook brought them to me. I took his toys away until school was over. Belle had to clean up the mess for the cook and write her an "I'm sorry" note at recess. Belle and I talked at recess and I believe the problem is solved and she will not do it again. She felt really bad. When she went to the rest of recess she was smiling.

So, any suggestions? Im not really sure what to do or how to handle this situation. She's only 5... I was scared to death to do anything naughty at school. The worst thing I can remember doing was being naughty at church and my dad made a paddle that day and I got a spanking I'll never forget. But. Spanking these days is abuse.

What to do.... What to do....