The Bobo case inspired IRS to issue a Revenue Ruling in 1983.  Back in those days, IRS issued a lot of Revenue Rulings.  They agreed with the Tax Court decision and elaborated on what they thought was important to know. For owners of trailer parks.  And actually, you can now find trailers on Airbnb.  

https://www.taxnotes.com/research/federal/irs-guidance/revenue-rulings/rev-rul-83-139/dfm7 

And then there is this from the Treasury Regulations, which are a higher authority than Revenue Rulings and (at least in the mind of IRS auditors) the Tax Court:

 (2) Services rendered for occupants. Payments for the use or occupancy of rooms or other space where services are also rendered to the occupant, such as for the use or occupancy of rooms or other quarters in hotels, boarding houses, or apartment houses furnishing hotel services, or in tourist camps or tourist homes, or payments for the use or occupancy of space in parking lots, warehouses, or storage garages, do not constitute rentals from real estate; consequently, such payments are included in determining net earnings from self-employment. Generally, services are considered rendered to the occupant if they are primarily for his convenience and are other than those usually or customarily rendered in connection with the rental of rooms or other space for occupancy only. The supplying of maid service, for example, constitutes such service; whereas the furnishing of heat and light, the cleaning of public entrances, exits, stairways and lobbies, the collection of trash, and so forth, are not considered as services rendered to the occupant.

https://www.law.cornell.edu/cfr/text/26/1.1402(a)-4