To prevent accidental double-punching, go to the menu on your clock, and enter a minimum time between punches.
Series 10 Fingerprint / Proximity Clock
Menu > System > System > ReCheck Min (Set to minimum # of minutes before another entry will be accepted.)
Series 300 Facial Recognition Clock
Menu > System > Log Settings > Dup. Punch Period (Set to minimum # of minutes before another entry will be accepted.)
Series 800 Facial Recognition Clock
For Series 800 Face Recognition clocks, see https://sundialtimesystems.freshdesk.com/solution/articles/1000264377-clock-tools-commands-to-prevent-duplicate-double-punches-on-uface.