This is a really interesting debate. I find myself agreeing more with the auditor but actually find any method is flawed. Steverogers point on "secured in place and secured from tampering" is what the issue is about, it's not just secured from tampering.
Why do I not agree with a "weighted" securing method? Well because they will go missing / get moved etc. Trust me. You can argue until you're blue in the face that it's fine with an auditor but the first audit you have where a box isn't where it's meant to be is an easy non conformance. If they can be moved, even if that's just being slid along the ground, they will be moved. Even if your pest auditor picks it up in their audits and the auditor then sees it, they're then well within their rights to say your method of securing the boxes is not acceptable.
That said, the typical method of securing with a wire is also fraught with error as often the boxes are turned in position, especially those used inside for mice as the boxes are light and easy to move with cleaning equipment.
I don't hold with the mode of connecting them being an issue though. I have never seen in my 20+ years in the food industry any building that has been damaged by connecting a pest monitor to it because there is normally a useful set of ironworks near where you'd like to place one or the wall is sufficiently thick not to be a problem.
Whenever someone comes up with a new way of doing something I'm minded to think "was the old way a problem?" Unless the new way is an improvement, which for this I don't think it is sadly, I know I'm going to have a battle on my hands with auditors.