MacBook Pro seems to consume gmail reminders?
Weird: Gmail had, for whatever reason, chosen to begin marking all my calendar event reminders as spam. I find them in my spam folder today, and this had indeed begun just a day or two after I got my MBP. Gmail claimed that it was sent to the spam filter because "It's similar to messages that have been detected by our spam filters." (in the header above the spam-filtered email).

The solution was to explicitly whitelist all google calendar event reminders, as follows.

I also had to clear and reset each of the default notifications for the calendar as here.

Now I can get on with my life.