Bag Ban at Waitrose

Waitrose, the UK grocery store, is amidst a two week trial where they are assessing the possibility of a bag-less supermarket.  The Saffron Walden branch is withholding all bags, encouraging customers to bring their own re-usable bags. 

The supermarket already has 14 other locations where customers can check out through "green tills," if they bring their own bags.  We assume the benefit is that the line is shorter because only a minority of people bring reusable bags.  But if the incentive for bringing your own bag is a faster line, how do they plan to compensate for the extra time it takes to pack peoples inconsistently sized bags? 

New Consumer: Free bags are banned in Waitrose trial