Serious Eats - seriouseats.com

I also think the common sense rule should apply to the customers. If you don't want you bread squished, don't put it up first followed by all your heavy items. Honestly, how hard is it to put like things up together. It makes everyone's lives easier.
As frustrating as it is for customers to have things bagged incorrectly, it's just as frustrating for us baggers to try to untangle your jumbled mess as you stare at us impatiently. If you're that OCD about it, do it yourself!