When you share a Proof and you aren't within the Proof itself the settings for Role & Notifications are treated as a "subscriber" even if the recipient is a licensed user with their own defaults setup. Plus, there is no place to change the default for a subscriber so they are ALWAYS Reviewer/No Emails. The only way to change the settings for that recipient is to go into the Proof Details and change the Subscriber settings each and every time.
There are 2 good solutions that should be programmed:
1. The settings when you share a proof from ANY "share" button should use the default settings for that user.
2. There should be a way to universally change the default for subscribers.