Now you're just making reasons up that sort of fit. That wasn't the purpose of the bag. There are less liquids going through xray machines now than prior to 2006. This is just as I predicted in 2006. As the years march on people forget the reason the rules were introduced and the rules take on a self perpetuating life of their own. People forget what it was all originally about and the rules morph in a sort of mission creep into new rules. There was originally nothing about the bag being airtight. The bag was to provide some sort of limit to the amount of liquids brought through otherwise people would bring loads of 100ml containers stuffed to overflowing out of a bag.