Birthday parties
You may write about your child's reactions after a birthday party. You may of course speak to the teachers directly instead of writing in the renrakucho. You may choose whether or not you wish to write about your child's attitude before the event. Since a birthday party is a school event, you are also not obliged to thank the school for the party. However, if you feel that the teachers really made an effort on behalf of your child, you may of course choose to express your thanks.