Cutting hours to be under 99%

I've been saying this for years but GM's should need to Clock in like every other employee. I've worked under 9 GM's and only 2 worked the 40 hours required. They come in late. Leave early. Take extended lunch breaks. Since their 40 hours count on the labor model (which I never knew until a year ago) why not make it happen. That's a huge step forward in balancing out the labor. Honest GM's shouldn't have a problem with it. The cheating ones can leave. I'm not suggesting they get held accountable points wise for being late or leaving early, yet if you are salaried at 40 hours but working 30, that's some BS