I was trying to trade out some tickets on my season ticket package for this or WPG. There were reportedly close to 1,000 tickets available for this, while WPG was a Saturday sell out.
For one, yes weekends tend to sell out, week days against lesser known teams (literally any team except the original six, which always pack the house with the other teams sweaters) sell less well. However, in any case, the near sell out represents tickets distributed, and there are apparently a lot of season ticket holders who figure they don't need to go to every game, as many lower bowl seats sit vacant. And, from watching ESPN highlights, it seems that way at nearly every sporting event these days.
I know for what I pay, I hate to skip any games, maybe only 5 in 25 years where I didn't give the seats away. I do normally split my tickets half and half, so can't say what my seat partners do.
I also hear that Galardi has reversed the JN policy of giving away large blocks of tickets to assure the stadium looks full, but there are many promotions. In stadium, you can always tell the true sell outs by looking up to the third level to see if those seats are filled, usually with walk up ticket sales.