It's too easy to place the addresses of correspondents in the 'To' and 'Cc' fields when 'Bcc' is intended. Mistakes are common and they can have serious consequences, whether for correspondents of a small association or of a public administration. They are also in breach of data protection laws and regulations.
Would it be possible to add an item to Account Settings that allows the user to mask the 'To' and 'Cc' fields in such a way that a deliberate action (such as searching in the menu) is required to activate them?