Quite apart from the possibility that Wai-Ping could have
found the report through an appropriate search, I would note that
s. 5(1)(b) requires an assessment of what steps a “reasonable person with the abilities and in the circumstances of the person with
the claim” ought to have taken. The Murphy defendants and the
Amerispec defendants are both experienced and knowledgeable
about the home inspection market in Whitby, Ontario. Indeed, the
Amerispec defendants are themselves home inspectors offering
services in the same market, and the Murphy defendants are residential real estate agents who frequently retain home inspectors.
 One would have expected persons “with their abilities
and in their circumstances” to be able to provide evidence on
the record explaining why it was “impossible” for them to have
discovered who performed the home inspection on the property
in February 1995. Were they unaware of the Hart defendants
prior to receiving the inspection report in October 2015? Were
there so many home inspectors providing home inspection services in 1995 in Whitby that it was impossible to ascertain who
might have performed an inspection on the property? The Murphy defendants and the Amerispec defendants fail to consider
these and other matters relevant to a determination of whether
it was reasonably possible for them to ascertain the identity of
the Hart defendants.
 The facts here are quite different from those in Galota or
Madrid. In neither of those cases did the plaintiffs have any indication of the possibility of a claim against other defendants.
As Lauwers J. noted [at para. 15] in Madrid, there is no obligation on a plaintiff to write “pro forma letters” inquiring about
other possible defendants “[ i]n the absence of an unexpected or
unusual trigger”. On the other hand, where a plaintiff is put on
notice about a possible claim they are under a duty to make further inquiries.12
 In my view, the existence of this positive obligation is
implicit in the reference in s. 5(2) of the Act to a “reasonable person”; the “reasonable person” standard requires a plaintiff to
demonstrate, on a balance of probabilities, that they acted reasonably in attempting to discover the elements of their claim. As
Lang J.A. found in Pepper, the plaintiff can discharge this positive
obligation only through the provision of an explanation as to why
the proposed defendant’s identity “could not have been determined through the exercise of reasonable diligence”.13
12 Madrid, at paras. 16 to 17.
13 Pepper, at para. 19.