A scent-free room asks comfort to include bodies whose reactions are not obvious to others.

Some reactions are severe and completely invisible from outside. Asking a shared space to leave out something most people would not notice is a way of including bodies whose difficulties are not legible, and it requires people to act on information they cannot personally perceive. Consideration here is a matter of belief rather than of observation.

So take the request at face value when someone makes it, without requiring them to justify or demonstrate. And where you set the terms of a shared space, ask what would need to be true for people you cannot see to be comfortable. Assume such people are present, because they usually are.