I take attendance (the old-fashioned way) in my college classes for a couple of reasons:

- Some students are "sponsored" by scholarships or organizations that request attendance data. - I want to know the attendance record for a student who is asking for an extension, or extra-credit work, or some other informal accommodation. - I like to draw fancy graphs correlating attendance and final grades.

But other than that, I don't care if students are in class or not. They're adults. Learning is their responsibility.