Why might lying be allowed for all members of the communtity after becoming twelve?

As far as we know, others may not lie after the age of twelve. Unfortunately, Jonah wonders this same thing and decides that if adults can lie...... how would you ever know they were telling or had ever told the truth.

Lying might be allowed for all members of the community after becoming twelve becuase they are more older & mature and they can make their own decisions if they would like to lie or not to someone in the community. Also , why lying might be allowed for all members after becoming twelve some teenagers in jonas' community might try to lie to fit in with a popular group.