Must agree with those who say that it won't make much of a difference to security, what with everyone being scanned anyway. However, TSA officials are already underpaid, undermotivated and overworked, and it's conceivable that this rule change could increase through-traffic at security by probably two times, and quite possibly more, leaving them even more overworked and increasing the liklihood of cockups. Besides that, most airports are crowded enough already, and there would be nothing worse than dodging a bunch of blubbing family members on your way to your flight which departs in five minutes.
By the way, Jafo, fun as it must be to be so culturally superior, perhaps I could ask that you keep your idiotic generalisations to yourself.