In what circumstances will a fiduciary relationship between a beneficiary and the beneficiary be considered to be unenforceable?

In Frame v. Smith, Wilson J. noted that the categories of fiduciary relationship are never closed. In order to determine which relationships that have not traditionally been viewed as fiduciary in nature should be subject to a fiduciary duty, Wilson J. stated at page 136 that fiduciary relationships tend to possess three general characteristics: (1) The fiduciary has scope for the exercise of some discretion or power. (2) The fiduciary can unilaterally exercise that power or discretion so as to affect the beneficiary’s legal or practical interests. (3) The beneficiary is peculiarly vulnerable to or at the mercy of the fiduciary holding the discretion or power.