This excuse was invalid, the tribes can pass through checkpoint of the gates that set up. This was in the best interest of the region but it faced great amount of opposition, I wonder why sometimes.
We proposed this in 2005 when the insurgency was still in its infancy and one of the reasons was that the BLA were freely moving back and forth between the borders. As a result of it not happening, we are standing here today with multiple cross border attacks.
If from pakistan point of view this was invalid then they should go with the plan and fence it, it is pak territory and has nothing to do with afghanistna side.