I think we must also recognise that there are lurkers who are "punting-curious". That is, people who would like to punt, but are scared or reluctant to do so, which might be because of nerves, fear, consequences, etc. We need to be considerate and supporting of these people, as once they have taken that jump they could become valued members of the board. In these cases, a draconian approach is not helpful.
OTOH, lurkers who are just abusing the system and parasiting off the reviews and experiences of others are best got rid of quickly.
We ordinary members need to trust the mods to deal with each case appropriately, which I think is better than having too many hard-and-fast rules.