Students swipe their IDs when they get on the school bus in the morning and when they get off. Each action also prompts a text message to the parent letting them know the location of the student.

School districts are increasingly looking at different kinds of identification technology to try and keep students safe as well as let parents know where children are located, according to a report in USA Today.

Cincinnati Public Schools and First Student bus company arte using the ZPass program to track student attendance. Princeton City Schools , north of Cincinnati, are piloting a smart card that enables students to use ID cards for everything from buying lunch to checking in when they’re tardy.

These uses haven’t caused any issues but when San Antonio school’s deployed IDs with GPS technology a student sued the district. Despite winning in court, the school discontinued the program.

“It’s really about how much do you want to know, how much you should know and where you cross the line,” Ronald Stephens, executive director of the National School Safety Center told USA Today. “There is a way where technology can be very helpful. It’s a two-edged sword.”