Restrict Select Notification Preferences to Admins
Admins are only able to set default notification preferences for all users and are not able to lock those settings. Individual users can easily turn off notifications by channel or topic. Therefore, users can turn off all notifications by email, bell, browser, etc. HubSpot should grant admins the ability to restrict access to notification preferences by channel and topic.
A short story on why this is a major problem:
I recently ran into this issue when I noticed a workflow was not sending an internal email to two of our users. I wouldn't have been aware of this if I had not been checking the workflow history for something unrelated. Both users had turned off ALL email notifications. All. Email. Notifications. As an admin, I can't see or change their preferences which made this difficult to troubleshoot and resolve.