Since it is so easy to game card-based check-ins, I'm sure the teachers still have to verify attendance. Also, if a student's card isn't working, they have to be able to count that student as in attendance. I wonder how much time this actually saves.

There has been quite a bit of push-back to the use of RFID specifically. My college used magstripe cards. They're not quite as robust, but they do need physical contact to read the information. It seems like a fair trade-off considering that these are a) kids and b) they are legally required to be at school (and by extension, school policies carry some force of law).