Entering configured node types into calendar is optional.

One can choose which content types have the event date entry input shown in this version of event.

This seems to be controlled from admin->content_types->(choose your type)->configure->Show in event calendar option.

All well and good, but let's say we have a forum, some for general discussion, some for discussion of events.

If you're starting a discussion on an event then all well and good, the user should enter dates and this should appear in calendar.

What if the topic is in a more general forum though? Sometimes no date is applicable. The start/end dates event block adds should be complimented with additional 'Add Associated Calendar Entry' or similar checkbox. If this isn't checked (or is unchecked - default should be configurable) then no calendar entry should be made.