How can I make Google Now ignore some calendars for appointment reminders? How can I make Google Now ignore some calendars? 

My wife's calendar is shared to my calendar and then synced to my phone through my account and I currently get reminder cards for her events in Google Now.  I would like to only get cards for certain calendars.
Apparently, Google Now uses the "My Calendars" section of Google Calendars.   

When my wife's calendar was shared with me, I was granted "Make changes AND manage sharing" rights.   This puts the calendar into "My Calendars" for both users' calendars. When I changed it to "Make Changes to events" on my wife's sharing tab, the calendar moves from "My Calendars" to "Other Calendars" for my account and I no longer get notifications in Google Now for that calendar.