This post from Johnnie Moore and another post from Euan Semple both resonated with me recently.
Managers really have to start treating people like volunteers and not conscripts.
Or as I so often put it "We must stop doing things to people and start to work together."
Its a principal I apply in my Knowledge Cafes.
People are not forced to come and then I quite deliberately do not force people to join in or try to manipulate them or the conversation in any way. (And yes I am aware it is impossible to entirely do that :-) )
I tell them that if they just wish to just listen that is perfectly OK.
And the final part of my Cafe, where I go around the circle and ask people to share one actionable insight with the group, I also give people the change to opt-out by saying "pass".