Three things to consider.
1. People do things because they want to or becasue they have to. Try to figure out how to make your high school group want to check in. I know you have to build incentives. Keep trying, maybe you just haven't found the the right incentive yet.
2. Sometimes it doesn't matter what process we change to as long as we change. You said you changed the location. Thats good. Now try the self check in.
3. Do you have genuine buy-in from all your youth leaders about check in?
Bob VanDerPloeg
IT Director
Discovery Church