Exactly, plus the smell of vomit often causes nausea and vomiting in it’s own right.
Chain puking reaction.
You old enough to remember Lard Ass from Stand By Me?
I’m a sympathetic puker. I see someone throw up and I instantly want to do the same.
I saw this happen on a large scale at the Atlanta Merchandise mart in 1996. Almost everyone on the 6th floor during a show in January were stricken with terrible flu symptoms within a few minutes of each other.
My wife was taken to a doc in the box as were several others, the doctors considered legionairs syndrome, but it turned out to be the flu. Everyone was affected and it wasn’t pretty.
Strange things happen.