Even if they try to do so, not all landlords are lawyers (or even necessarily have English or French as a first language). They can think they understand something but actually not, or miss some of the fine print altogether.

These issues are going to fall disproportionately on the kinds of people who rent out a single basement apartment or the like, rather than the corps that own hundred-unit buildings and can afford to keep a lawyer on retainer to look at all of their contracts.