Sure you can defeat it using specialized tools... but at that point, you are far from "all I need is a pen" and opportunistic attacks. The tool will have to mat

Sure you can defeat it using specialized tools... but at that point, you are far from "all I need is a pen" and opportunistic attacks. The tool will have to match the width of the zipper: you'll need a collection or to have done reconnaissance. At that point, shimming the zip-tie itself is probably easier/faster (and doable without specialized tools).