Originally Posted by
GoingAway
"Black Diamond lines is TSAs mistaken attempt to circumvent the premium lines at many airports ... they wanted one to replace the other. They don't like the premium lines because they its an airport/airline concept/control point. The big difference is someone actually vets the people using the line with the premium lines, and as you saw its a free for all with the black diamond and TSA lines.
TSOs cannot and should not demand you use one line or the other, they can direct, but you can ignore. At IAD, they use non-TSOs for the line monitors to direct people and I nod at them then ignore the direction and select whichever line I want. It's the same regardless of whoever is doing the pointing, unless you are specifically directed for purposes of special screening."
Regarding paragraph 1, actually, it was to make the screening process more efficient yet not create anxiety by rushing people through faster than they were able to, as in the case of families with children, disabled persons, etc.. At no time since implementation have premium lines been taken away and currently still exist, at MKE at least. Link below for those who want to read it from TSA's site:
http://www.tsa.gov/approach/black_diamond.shtm
Regarding 2nd paragraph, I believe I already stated that. I agree with you here. However, there could be infrequent situations where you would need to use a different lane, such as if the X-ray machine goes down or TSA finds something in a pax's bag that warrants a lane change or evacuation.