RobDale - the point about this kind of thing putting another barrier in the way of any decommissioning by the IRA is based in the history of the Troubles.

In 1969 the IRA had in effect got rid of its weapons, and when thing blew up with loyalist mobs burning communities out of their homes, they did so without facing armed resistance. The sequence was a break up of they IRA with the more militant faction re-arming and becoming the Provisional IRA.

If the IRA were to decomission in the middle of what is still a militarised and violent situation, it would probably destabilise everything. It would inevitably, given that history, be seen by many people as a betrayal. The fringe republicans organisations who had held on to the guns, and who oppose the agreement, would move in from the fringe to be seen as protectors against sectarian and mob violence.

If you are defusing a bomb, you have to move very carefully if you don't want it to explode.