IN many parts of Europe, I've seen people shrink wrap their luggage, like so:

https://media-cldnry.s-nbcnews.com/image/upload/t_fit-760w,f...

I think it serves a similar function.

Use the zip-tie to "anchor" the slider too... that will defeat the pen trick.

Nope. Just stick a pen right through the zipper itself.

Don’t need any slider for that attack.

Yes, we're talking about an attack against the zipper (and not the zip tie nor the bag)

The goal here is tamper evidence... sure you can open the bag through the zipper but you won't be able to close the zipper back if you can't move the sliders.

I dunno, I think something like [1] could do a pretty good job of putting the zipper back together and then you would just have to remove the underside component at the very end and then jiggle the existing zippers to hide the fact that it had ever been opened that way.

I suspect there might be even more surreptitious versions of such tools.

[1] https://guide.sportsmansguide.com/tips/camping-101-quick-fix...

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).

Superglue works well too

This is what I do. The key is to use the small size zip ties and leave it little bit loose. Then you open it by putting a hotel pen in the loop and twisting, rather than needing a sharp implement.

One can easily cut the zip-tie, search and re-zip it again, right?

Yeah, but you can get zip ties that are uniquely numbered and colored. They’re meant to help ensure that cargo shipments get to their destination without being tampered with, which is exactly the kind of threat model we need to use against the TSA.

Yes, those could be faked. But your regular joe TSA agent isn’t going to be able to do that, just like your regular 18 wheeler driver isn’t going to be able to do that.

If you’re dealing with someone that wants to break into your luggage and they can fake the uniquely numbered and colored zip ties, then you’ve got a much higher threat on your hands that you need to deal with in other ways.