One thing I found that worked pretty well for getting people to get to practice on time is you don't wait for them to show up. Practice starts on time. If I say practice starts at 4:30 it starts at 4:30, whether there is one kid or 12 kids. People seem to get the idea pretty quickly.
You might also mention that you know they want the kids to get out on time so you're not sitting in the parking lot for a half hour. You will commit to that if they will commit to getting the kids there on time. But then you'd better follow through on your end!
You might also mention that you know they want the kids to get out on time so you're not sitting in the parking lot for a half hour. You will commit to that if they will commit to getting the kids there on time. But then you'd better follow through on your end!