[PeterisP]

If I have two tabs open, click "erase history" and one of these two tabs gets discarded, I have "used browsers correctly" (unless using the browser-provided tab functionality is always wrong) and still lost current application state. In such a situation there is no mistake to learn from, just broken user expectations (since no other browser does it that way) i.e. broken UX.

Also, I must point out that your choice of words with respect to users who have different habits than you - "PEBKAC", "need to take accountability for not using browsers correctly" is condescending, arrogant and simply rude - please do not do that. Not respecting users' choices and behavior is not an appropriate way to design user interfaces and is not an appropriate position from which to argue how user interfaces should be implemented. If browsers provide functionality for more than one tab, then browsers must work properly for more than one tab. In this case, the expected functionality for n=2 is the same as for n=1000, so the number of open tabs is not particularly relevant.