I agree Albert Hall. This was something that did not really need to be fixed right now with. Yes it did need to be fixed but could have waited. A failiure of this will be added to their already long list of 2017 and a success will pass almost unnoticed.
In the main part, I suggest, pax have become innured to the current process. Over the last 20+ years of moving to too much hand luggage, folks know how they handle it. It might not work well - but it works. So change is a greater risk for them at the moment.