In the offseason, teams will paint their stadium seats random colors to help camouflage the empty seats.
I find it interesting that in most photos showing empty seats most of the empty seats are in the upper decks.
Your comment reminds me of a story about the New York Jets back when the American Football League was just getting started ... maybe early 60’s.
The league reported the attendance at one game as 45,000. One sports reporter said “Sure, that’s true if 30,000 fans came disguised as empty seats!”