This value should be set on the server to which users auto-sync their work. This setting has no affect on client repositories. The check-in lock mechanism is only effective if all users are auto-syncing to the same server.
Check-in locks are an advisory mechanism designed to help prevent accidental forks due to a check-in race in installations where many user are committing to the same branch and auto-sync is enabled. As forks are harmless, there is no danger in disabling this mechanism. However, keeping check-in locks turned on can help prevent unnecessary confusion.