If enabled, the studio password will be required when undo-ing sign in and sign out. If disabled, user will be able to undo a sign in/out without entering a password. Some studios like to enable this setting to ensure a manager is involved if undo-ing an erroneous sign in, rather than allowing a volunteer to undo signing a dancer in on their own.
You can edit this on the Show details page by going to Show>View All Shows in the sidebar and clicking the Edit button next to the show name.