It's so critical for all of us to determine our own preferred protocols. If you focus on sharing information that's important to you, helpful to others, relevant to the discussion and with the right people, you'll be ahead of the information curve.
When people come together in groups, there's usually at least one member who slacks off. Whether you call it shirking or social loafing, it's a major source of misery, and it prevents teams from achieving their potential.
When we're being undermined by one person, we recognize the importance of seeking support from someone else. But it may be even more critical to invest in those supportive relationships when dealing with someone who's guilty of both undermining and supporting us.