This text in the Owners's Manual says:
This notice can be sent automatically when you add members to the group directly. You can customize the text further, if needed, at the time you are direct adding someone, but be aware that the further customization is not saved to the notice—it applies only to that one-time use.
The third word 'can' wrongly implies the possibility of not sending such a notice.
A Direct Add notice is always sent. If the owner or a moderator has not created a custom notice and set it to Active Message, the system activates and uses a default.
Yes, it's always sent but this implies the owner can supply a complete replacement message. What is actually sent is THE notice with some optional additional text from the owner.
Malcolm Austen <malcolm.austen@...>