It always happens to me too!
It doesn't matter who I fly with, They always put me between the two biggest guys on the plane. (I'm 6' 0" 260 lbs.)
I guess now, people will feel discriminated against for having to shop in the Big and Tall or Plus Size clothing sections.
It Happened To Me, Too.... There I was, heading home from Schofield Barracks, Hawaii. Uncle Sugar was paying my way, but the next seat over was a large fellow, no,a Very Large Hawaiian Guy. ("persons of size") rotfl I felt sorry for him just about till I had to sit next to him. For his part he allowed that he was rather large and he apologized and I'm sure it is embarrassing. In not-so close quarters I'm sure he's OK fella. I'm not exactly a lightweight, over 200 and 6'2", luckily their were some extra spots...
In the law of unintended consequences, they could start charging people by the pound... "Step right over here ma'am and we'll get a quick poundage for your ticket."