Q: Shared Calendar notifications

Me and the wife shares our calendars. This is very good in many ways, but  I also see all her notifications in the Mac notificiations center.

Even though I have the "Show shared calendar messages in Notification Center" disabled. (In Calendar > Preferences > Alerts)

It's extremely annoying! Is this standard behavior? If so, what is the "Show shared calendar messages in Notification Center" checbox for?

Tia,

Andreas