Occasionally, works incorporate names, titles, or slogans whose utilization is subject to restrictions by other laws. As these restrictions have nothing to do with copyright, the incorporation of these elements does not prevent registration. Where the Copyright Office is aware that a use of certain elements within a work may be in violation of existing law, it may inform the applicant of the possible restriction and direct the applicant to the agency involved. Some examples of restricted names and characters are: "Olympic," "Olympiad," (36 . 380): "Woodsy Owl" (18 . 711a): and "Smokey Bear" (18 . 711).
I see nothing wrong with writing (highlighting, underlining, whatever) in the margins of one’s own books that a person plans on keeping. But one thing to keep in mind is that some college students sell their textbooks when they are finished with them, and if those books get purchased and then resold, the next student may not want all that writing and highlighting in those books. And if a book has too much writing, it may be harder to sell than one without writing. One really neat idea I’ve seen is when students make notes on those note tabs they can stick inside their books; they’re only partially sticky, they’re not permanent, and they peel right off. Otherwise, if you plan on keeping your books, notes written in the margins can be pretty handy.