Generally, Canadian foreign investors abroad do not support this idea for the ISDS mechanism, because such mechanisms are often used to enforce the obligations contained in the international agreement. However, these obligations are not always imposed the same way in all jurisdictions. It must be recalled that the reason this mechanism exists is to give Canadian foreign investors, and foreign investors in Canada, the assurance that they know the basic rules.
Investors can always commence proceedings in a domestic court, here or elsewhere, when domestic law appears to have been violated. However, what's involved here is obtaining compliance with rules of an agreement that will not necessarily be enforced, or that will not be enforced the same way in each jurisdiction. Everything depends on the country. Therefore, if you require investors to exhaust all domestic legal remedies before referring the dispute to ISDS, there's a risk of losing a lot of time in court for a question that's not at the root of the problem.