This was the questions that Greenwood J had to answer in the recent Australian Federal Court decision in Key Logic Pty Ltd v Sun Holding Pty Ltd 2021 FCA 208.

If the email is sent in circumstances which impose an obligation of confidence of the recipients, the email will not be considered a publication of the design, even if it is sent to a cohort of recipients.  

In order to make this assessment, the court will look at, amongst other things, the main arrangements - including financial arrangements - between the parties; the underlying business purpose of the relationship and the reason for the communication or disclosure.  The party alleging the confidentiality of the communication will have the burden of establishing that the recipients of the communication were under an obligation of confidence.