As a historical example, there were TVs with built-in VHS and/or DVD players, but the other stuff got obsolete long before the TV did.

Having it in the syllabus doesn't make it valid, but it does create a burden that you should have known it was going to happen, and should have taken steps (dean, police, lawyer, etc) before the incident took place.

Many times I read a syllabus and drop a course right then. Or, I'll ask for a copy of the syllabus when deciding whether to register for a course.