SOP Comment Line - 'Show on customer documents' default setting

When adding an item on to a Sales Order, with the Comment line item type, there is a tick box for 'Show on customer documents' which is always ticked by default. Customers who prefer to use comment lines for internal notes have to manually untick this option each time a comment is added. Could an option be added to the SOP Settings to control whether 'Show on customer documents' is ticked by default.