If SmartBatching - Auto Batch & Settle: is enabled: The transactions will not be lost. If the you do not manually settle them they will automatically batch overnight when the scripts run.
If SmartBatching - Auto Batch & Settle is disabled: The transactions have the potential to be lost. They will void after 7 - 10 business days. So, yes, the business does need to make sure to manually batch the transactions before they are voided.