I think throwing chalk could just be gaming metrics. If people are interested it shows that what's happening is valuable, they benefit from what's being presented or have input that the presenter needs and they want to get that across. What the organization should care about is not that people ask questions or give feedback, it should care that time is being used well. That is we know this meeting isn't a waste of time because people are interested active participants and if people just sit quietly and wait for thing to be over maybe it wasn't that useful.

When you force people to talk you are getting the metric (people asked questions) but because you are forcing it the metric becomes disconnected from what you actually care about - was this meeting a waste of time. You haven't actually improved things you've just obfuscated the problem.