Some prof's don't require attendance.  Others allow a set number of absences, and then claim to lower the student’s grade.  Whether or not they actually do lower grades based on lack of attendance is not known.  Unfortunately, there's only one way to find out!  Most students will miss a fair number of classes in each subject over the course of the semester.  The usual reason is that they weren't prepared and were afraid of being called on in class. 
    As for the classes with no attendance requirement, there will come a point in your first year when you ask yourself why you're struggling to prepare for the class.  Why not just stay home, do the work and show up for the exam.  There are students who will do just that.  In reality you don't need to attend class to learn law.  Clearly the Prof is not inventing the law.  The law exists in other forms available from sources other than the prof's lectures (sources like the support materials we discussed earlier).
    The problem with not attending class is that you won't get the Prof's comments.  And remember what we said about grading?  C students quote law, A students quote the professor.  Another factor is what type of learner you are.  If you think you learn better through an audio style (listening to the Prof) or a visual style (reading the subject on your own.).
    It's true you can copy the notes of students who were in class, but understanding others writing style can be difficult and cumbersome.  Further, the words may not carry the same meaning they carried when delivered live.
    If you aren't shooting for high grades and think class attendance would not benefit you, then by all means try the non-attendance route.  But I must caution you, make sure you understand that Prof's attendance policy very well, being sure she really does not require attendance.  Seeing those words in writing on the syllabus would certainly be preferable. 
    Law school is a funny place; grades given by the prof's are basically non-appealable.  You can usually request a re-read, and if granted the Prof will go over your exam again.  But if your grade was dropped for non-attendance, a re-read won't be the solution you'll be looking for.