The idea is pretty cool when you start to think about adding self-destructing properties to individual pieces of data, so reasoning about data type and entropy becomes a risk modeling problem.
A concrete example: imagine if bank account numbers, credit card numbers, emails etc have self-destructing properties where there exists an outer shell "pointing" to the data but the underlying data is destroyed (using techniques like crypto-shredding et al.). The outer shell would have canary properties that work in real-word systems but since the underlying data is destroyed, all we would be left with are canary properties without the underlying data leak.
A good example of some companies that offer something similar:
- https://canarytokens.org/generate
- https://github.com/thinkst/canarytokens
Pretty cool technology that can really go far.