Email Merge-Field Fallbacks

Mailchimp lets an audience field carry a default merge value, so "Hi " reads "Hi there" for a contact with no first name rather than "Hi ". Here it would be a default per bound column, stored beside the email's datasetReference and used by substituteMergeFields when a row's cell is empty.

Why deferred

The exported files are read by their sender before they go anywhere, since nothing sends them (email sending); an empty cell is seen and fixed in the source Sheet or survey. A fallback earns its line when a send goes out unread.

Revisit when

Email sending un-defers, or a dataset whose empty cells cannot be filled at the source is bound to an email.

Cheaper interim

Fill the empty cells in the bound Sheet, or word the sentence so it reads with the field empty.