Wow, what a next level magic trick enabler. Just me that get the feeling that I am reading a documentation that could be under NDA in a billion dollar magic trick company?
Still, compared to other possibilities, you take what you can get.
The bar-code and shipping container are probably some of the greatest inventions of the 20th century, and unlike a shipping container it's completely appropriate and accessible to individuals for messing around with projects.
(no, your shipping container home is not actually a good idea)
IIRC, that's a matter of personal tolerance because the degree of error correction can be arbitrarily adjusted.
People underestimate how much can be done with spectrographic watermarks like that, they're resistant to scaling (because harmonics), rotation and flipping (because it's not about any one position... it's about the beat frequencies between them), translation (of course), etc. That's iirc how the Eurion Constellation works - the patterns form a spectrographic fingerprint, but in 2D instead of just a 1D beat frequency. But it pops right out of a fft so you can put it into random copiers and printers.
I went to look up a source to describe the Eurion Constellation scheme (I'm not sure if an academic description exists given the commercial and sensitive nature?) and they brought up the practice of microprinting (of the super fine lines) and that probably is detectable with FFT and edge detection.
https://murdoch.is/projects/currency/
I wonder if phase (of micro-printed regions) would also work similarly to how frequency fingerprinting does?