so people aren't really making a huge leap of logic to assume this is a bag that is designed for the purpose of taking liquids through security.
Ah, yes. However, the people who staff security are not normally equipped with the skills that permit huge (or even minor) leaps of logic.
I'd be tempted to write to the management of MAN and let them know your dissatisfaction and ask them to clarify if the Zip is OK or not. We know it should be, because
MzG said so. It would be interesting to see if the left and right hands knew what they were doing......
If you do get confirmation, please post it up - it will help if I get picked on again. Meanwhile, I'll just keep forgetting my liquids are in my bag