We definitely had some empty seats by us. We were still really packed in though. I wonder if some people found better places to habitate as we had a pretty major snow issue in our area.
Also, my friend went to the bathroom with 7 minutes left in the second quarter. He said there was still a line at security to get in. I think a lot of people had parking issues and got in late.
As far as STeelers fans, there was an OK amount. Probably not as much as there would normally be (weather, Monday at 4:30, heavy underdog). There was one fat troll in our area who was going nuts and 'talking trash' to the Bills players after every positive Steelers' play. Like he was on the field playing or something. It was super obnoxious, and I have a high tolerance and welcoming attitude toward visiting fans. If that game went south, I really think someone would have gone on the offensive.