Confiscation of class notes depends on your school, level of education, and location.
I am not a lawyer...
However, laws have been changing gradually giving parental and personal rights to schools and government. When your child is at school, both the child and personal items with the child can be deemed as property of the state. In some locations, laws give legal guardianship to the government and school during school hours.
If you are in college or university, a forced personal search and confiscation is usually not legal. A professor or school can make part of the curriculum (by syllabus, school handbook, etc), turning over your notes as part of your class grade. However, pre-notification of curriculum is required. Students have the right to make personal copies before turning in notes, or refuse to comply thereby accepting the grade punishment. Once you turn in something, all schools (including colleges and universities) own the copyright thereby preventing you from legally re-publishing the content. Turning in an assignment is an act of publishing and transfer of copyright. You can still have the copies for your personal use, just not redistribution or re-use as inclusion in other assignments. This means you can get academically or legally punished for plagiarism if you re-use any portions of your own work and notes.
It is unfortunate that parental and personal rights are being removed. Be aware of the laws that affect you and contact your government representatives about your concerns.