I don't know what that has to do with generations, because I think things like this are also done by many people (of other generations too). It is more about ignorance and indifference towards the security of the assets they own, that they don't realize that importing something as sensitive as that in a public place not only endangers their assets, but also their own lives, as there have been many cases of invasion and being held hostage because they don't care about their security in public places. People like this will usually, sooner or later, learn how valuable their privacy and security are.
Before I even say anything, I hope you have read what others are saying too? As you can see I am not the only person that sees how Genz are behaving, so yes a huge part of this has everything to do with GenZ.
Your point about other generations doing the same could be valid in your country or city but in mine it's different, since I have been in crypto space this is since 2016 I've never seen such behaviour until recently.
If people are backing it up like they do it's means they are noticing the same habit too, Genz don't know how to do things on a low key, if eventually crypto wrench attack becomes bigger GenZ will be the most affected.