This is a tuff call for the Prof…
It should be a discretionary call based on the persons ability or want to contribute equally, give and take, in the forums. That’s what it’s all about.
Don’t go the way of setting hard and fast rules or votes etc. because it then becomes pseudo political and that wouldn’t add to the great chemistry of this forum.
If people want in that never post then its reasonable to assume they are gathering info rather than adding to the pot!
Good luck on this one Professor!