If the site becomes popular e.g. "#1 Landlord Review Site" then everyone will be checking their reviews on it. If it's never popular and not used often then it doesn't matter if it's clear text or not.
I think you fundamentally misunderstand or have yet to convey how such a site would solve the problem of distinguishing “I am a tenant looking for reviews of a property” and “I am a landlord looking for reviews of my property”.
I never stated it does. You are the one driving at this point as if it were the only issue, or the most important issue, which it is neither.
What it does solve is the problem of this data being visible to every landlord who types the address of their property into a vastly more popular search engine known as Google. They need not even know of this site, it gets served to them on a silver platter.
And if you think a robots.txt alone solves that, you’re mistaken. A robots.txt is just a recommendation. Web crawlers are not obligated to honor it. The only way to solve it is to make sure the private data isn’t even there in the first place.