Common Sense Statement:
This syllabus is not a contract but has certain contract-like qualities. It describes what you are expected to do to succeed in this course, and implies your commitment to do it.
I describes the rules and means I will use to evaluate you, and imply that I will aim to follow them. I can and will make changes to any point in the syllabus if I see it beneficial to you and your education: eg: if the campus were invaded by rabid coyotes during the finals week, I would probably find a way to calculate your grades without you taking your final exam.
I assume that you understand the standards of academic and civic behavior and commit to respect them, yet I do not describe everything you are not supposed to do in this class and which, if you were to do it, would have some effect in your final grade: eg: it does not explicitly forbid you to jump on your chair, remove your clothes and sing 'The Marseillese," nor what would happen if you repeatedly did so. (You cannot, and you would fail the class).
Q: More ideas?