You can opt to not allow appointments to be made outside of your operating hours. This feature is available for the Grooming, Daycare and Special Services modules.
Click on File, Business Info, Operating hours tab.
Check the box for 'Enforce operating hours'.
Enter your hours.
When you make an appointment, you will need to enter an in and out time. If not, you will get a popup message.
You will also get a popup warning if the time is outside of your business hours.