What was great with my ticket grooming bi-weeklies was that despite having 20 engineers in a room, we were strongly admonished from going into technical details of implementation in the room. "Take those offline. But please put a size on the ticket, thank you."

What else do you want us to do for 4-6 hours/week? Write poetry?

Eventually every ticket just gets sized "medium-big", and people keep their heads down with mouths closed.