Hello Laura,
I like your incentives.
At my institution, we have a strict attendance policy. If a student has more than 8 hours of missed time in a class due to tardies and/or absences, the student will be withdrawn from the course. A tardy counts as 1 hour of missed time, and an absence counts as 2 hours of missed time. If at the end of the grading period, a student has perfect attendance and an "A" average, the student will be exempt from the final exam. Students really strive hard not to be absent or tardy, and they work really hard to get "A's" so that they can be exempt from the final exam. Also, at the end of the grading period, as an institutional policy, 5% of the student's grade comes from attendance and 5% comes from participation. By having the policies in place, students' tardies and absences are kept to a minimum.
Patricia