This is some great advice. The biggest reason for clogged calendars is that managers use meetings to "get updated". Meetings are expensive - they should be for "crossing the finish line" on complex issues - i.e. deep discussion to reach a shared understanding.

Everything else can be done as the need arises - and by being proactive and going to individuals and and asking questions. We go into this issue at length in the Agile 2 book.