I, too, am very silent when the girls are in trouble. Its not so much anger, as it is silent frustration and even sadness. Silence is better when you can't form words to have a talk with them anyway.
What was today like? Did you let W know about the problems? What does she think? With S7's issues, I am sure its harder to discipline him (taking away fun things, keeping him home during outings, etc).
