Given the venue sizes it'd be amazing if they were.
Whether being a more peripheral fan = more drink/toilet breaks I don't know, possibly. Whatever the reason, it can get ridiculous. I'm sure there's partly an element of the "CONSUME! CONSUME!" urge. "A short walk away there's drink and food. I MUST HAVE SOME!" "Look there are people getting drinks. I MUST TOO!" Plus, over my decades of gig-going I've seen that regular combination of rock gig, men, beer. It's one of the fundamental laws of the universe. Lots of Rock Gig Blokes feel they are under an unbreakable contract to pour as much beer into themselves as possible at rock gigs.
(See also Ill-Fitting Tour Tshirt Stretched Across Belly syndrome).
I guess we got lucky at the show in DC. Once the concert started we didn’t have a single person in our row get up. In fact we were sitting along an aisle and I noticed just 2 or 3 people in our entire section sitting in rows above us walking by and coming back. There was a younger looking couple sitting above us who seemed to leave about half way through the show, but that’s about it. In the row right in front of us a young African-American gentleman (early 20s) sat alone and sang along to every song. Perhaps the fact that we were in the “cheap” seats (upper bowl, far end from the stage) made a difference in terms of people coming and staying for the entire show.