Now, talking about exceptions, I am not a technical person, but I am just imagining that there might be a way, or better put, loophole through which those who have good technical knowledge of wallets (and how they work on the development side of it) might know how to figure out if two or more addresses belong to a single wallet, this I don't know and have not heard of, I am just speculating here, and I hope I am wrong.
Technically it is impossible to know if two addresses are linked (whether from the same wallet or have any connection whatsoever). All we can do and all the blockchain analysis companies do is report the likelihood of it being linked.
For example one thing they do is to speculate which output is the change address (eg. round number is payment, the other is change) and claim that it belongs to the same wallet. But this is speculation and we still can't say for sure.
Another thing is claiming that inputs of a transaction coming from 2 different addresses links those 2 addresses but again this is speculation.