Vapor Barrier
The toilet stall between two occupied stalls in a men's public restroom, that according to etiquette, shall remain empty during the time for which the aforementioned adjacent stalls are in use; that also provides a "safety shield" against unwanted physical contact and aroma.
Public Restroom Patron #1; {sitting in stall "A"}
Public Restroom Patron #2; {proceeds to enter stall "B"}
PRP#1; "Whoa there, Senator! Mind the Vapor Barrier!"
Public Restroom Patron #2; {proceeds to enter stall "B"}
PRP#1; "Whoa there, Senator! Mind the Vapor Barrier!"