I propose that when the professor merges multiple sections of a course together on Canvas, then the students can see the rosters for all sections, not just their own.
For a given course, there are times where multiple sections meet together (same time, same professor). Combinations include graduate and undergraduate students, or honors and non-honors students. (For this example I will be using the two groups of honors and non-honors students.)
The professor can combine the sections on Canvas to only post material once and both groups (honors and non-honors students) will see it. However, currently students can only view the roster of those in their specific group: honors only sees other honors students; non-honors only sees other non-honors students. There can be projects where the groups are mixed: honors and non-honors students work together. A student can want / need to email everyone in the class as well.