Hi Richard,
I did a poll in my research center and it turned out many other people had a similar expectation.
E.g. Given an identity matrix, of course the eigenvectors should not be unique up to a permutation since this is a degenerate problem (any rotation or reflection will be equally valid). However, people still tend to believe the result is going to be at least orthonormal.
I think this hidden bias are shared by many more people. In the document, there should be a warning on this and always suggest users to use symeig() if the matrix is Hermitian.