Notification for people who haven't signed waivers

I have a lot of students and prospective students at my gym and it's hard to make sure they have all signed a waiver before stepping on the mats or if they have followed up with any updated waivers. I would be interested in a system where I can either check to see how many people in the system have not signed any waivers at all or a system that would notify me if someone who hasn't signed a waiver tries to check into a class. I know systems like Zenplanner and others have both of those features.