These settings will only remove visibility of the calendar to view and prevent them from making bookings, it will not remove the Dinner tab - this allows parents to view balances and historic dinner transactions, and pay off any debts.
Please note: If you would like to remove the tab completely, the dinner plan needs to be made inactive using the de-activate button - reports can still be accessed and charges/credits can still be recorded. Dinner plans can be re-activated in future if required.