[pjc50]

There is a big distinction between houseshare (two people on an equal basis jointly renting from a third party), renting (one person is the property owner and the other isn't), and subletting (the person in the middle is both renter and landlord).

Only the first can reasonably counted as equitable sharing.

[cactusface]

On reflection, I concede that AirBnB is largely landlords renting their space or tenants subletting for substantial profit without their landlord's permission. However, I think subletting is fine, as long as you aren't making a substantial profit without your landlord's permission. I've sublet many times with my landlord's permission, it's regulated by tenancy laws, etc.