R.E.M. and B.M. (also Griecken, [2009] O.J. No. 5037 at 24 — 25) cite Bell, [1997] N.W.T.J. No. 18 (CA) at para 28:... Where, as here, expert evidence is offered by the defence, in its efforts to make
full answer and defence, a
trial court should not impose, as noted in Mohan, too strict a standard for the
necessity of such evidence, especially where as here the witness recognized the need to avoid crossing into the jury's domain.