I am drawn to zips for travel as well. I also have Global Entry but isn't the issue if the footwear has a steel shank? I had to remove some Alden boots going through the TSA-pre line since they set off the buzzer due to the steel shank. Vibergs have steel shanks, don't they? So a side-zip Viberg would be easy to remove.
10/23/16 at 4:09pm