In what circumstances will a trustee be liable to the beneficiaries of a trust for failing to keep accurate accounts?

"[W]here there has been a negligent failure to keep true accounts, or a refusal to account, all presumptions will be against the trustee upon a settlement. [Citations.]" (Purdy v. Johnson (1917) 174 Cal. 521, 527.) In such cases, liability may be imposed regardless of intent. "[C]onceding the good faith of the trustees, the fact remains that they had, by their own admission, failed to comply with the obligation which rests upon all trustees to keep full and accurate accounts of the trust funds coming into their hands, and to render an account thereof to their beneficiaries." (Ibid.) Thus, to the extent that trustees are unable to establish the accuracy of their accounts, "the computation must be made upon the basis most unfavorable to them." (Id. at p. 530.)