First-class cabin fuels 'air rage' among passengers flying coach, study says - Los Angeles Times
Researchers report that the simple presence of a first-class cabin on an airplane is correlated with an almost fourfold increase in the frequency of “air rage” incidents in economy class.
And when economy-class passengers are forced to pass through the luxurious first-class area on their way to the cramped economy seats, the rate of air rage incidents is more than seven times higher than if there are no first-class seats at all.
On average, these incidents occur in economy class just .14 times per 1,000 flights when there is no first-class cabin, but 1.58 times per 1,000 flights when there is a first-class cabin.
Among first-class passengers, air rage incidents occur 0.31 times per 1,000 flight
https://www.latimes.com/science/sciencenow/la-sci-sn-air-rage-first-class-20160502-story.html
