When using the 'send in bulk' feature (formerly Mega Sign)the preview should give you a view of at least what one of the sent requests will look like (pre-populated with details pull from spreadsheet). Ideally also some information on how many users it will send to and which fields will be populated. E.g. if there is a mapping error it would be easier to spot on the preview and fix the spreadsheet. Possible a second preview page before sending.