so yes, the plugin itself still sits directly on the storage and hence to submit changes you still need the permissions (to manage reminders for snooze/dismiss).
But the plugin also provides light dbus service which allows you to read all calendar events over DBus async-ly:
fire id=org.nemomobile.calendardataservice.getEvents s:start s:end
and then be ready to catch consequent signals
org.nemomobile.calendardataservice.getEventsResult s:id a(sssssbssss):events

but now as i look at it... the event does not have reminders bundled into it. so we wouldn't be able to block system and use internal we then still need permissions - either to fetch full event struct with reminders - or to submit changes to cal storage.