Answer to Question 1
Answers are likely to vary here. The crux of the issue is the extent to which the notes are distracting students' attention away from the topic at hand. A quick note from one student to another may be relatively harmless. However, a lengthy exchange of notes back and forth indicates that students probably aren't paying attention to the lesson.
Answer to Question 2
Perhaps Becky's California teachers encouraged cooperative group work and other helping behaviors fairly regularly. In contrast, Mr. Matherson is obviously expecting that his students will do their work without others' assistance.