David,

Here are my off the cuff reactions.  

At least from the US perspective, it might be useful to distinguish between forms of academic writing. Specifically between "doctrinal" writing (treatises restatements,  and various legal encyclopedia's, that are in the business of organizing, collecting, and  collating doctrine), and the more theoretical scholarship that is in the business of justifying, reforming, expanding /contracting  established doctrine. I think most judges, lawyers and scholars would recognize that these are somewhat different genres of writing, such that citations to the restatement, while techincially an "academic" work, is unlikely to lead to much interest or citation of writing more typically concpetualized as "academic legal scholarship".  In other words citing Prossor on Torts or Wright and Miller of Fed. Jur. is not really understood as citing "academic" scholarship-- despite the fact that these works are/were written by academics and inevitably promote some view or conception of the existing law.

I cant speak to Canadian tort cases, but I would not surprise me to learn that there is quite a bit of citation in US courts to the doctrinal materials, in large part because unlike in the CWealth, there is less of an established canon of "leading cases" that define each field.   But I don’t think that this leads to citation of the theoretical scholarship-- which is understood to be of a different kind.

Finally, while I know far less about torts specifically, at least in the restitution context,  the English HOL cases are far morelikely to cite theoretical academic scholarship than US cases.