It's a good question. I think that we always have to start from the perspective that it is up to a complainant to demonstrate that they have been discriminated against on a ground that's contained in the act, even for other grounds.
For example, family status right now is a ground in the act whose interpretation is not yet established, and there are different views—legal views, academic views—about what this ground means. With this ground, as with any ground, it would be up to a potential claimant to indicate to their employer, their landlord, the service provider—the potential respondent—that they believe they are being discriminated against by that person on this particular ground.
In that sense, this is something that regularly occurs: the complainant has to take some steps to notify the person they believe is discriminating against them that they believe they are being targeted on the basis of a prohibited ground.
It is true that different grounds have differing degrees of established meaning. I don't want to take the hate speech analogy too far, but it is an example of a situation in which, when the test that the Supreme Court has come up with—in 1990, in the Taylor decision—is one of whether the victim feels attacked on the basis of deeply felt feelings of vilification or calumny, there is a subjective component to it. It's true that tribunals and courts have struggled with a definition that is more a subjective than an objective one, but I would suggest that it's a difference of degree in many cases, as opposed to a difference of kind.