Have you ever sat on a chair with a thick foam cushion only to hear the air whoosh out as you gently sink into it sort of whoopee cushion-like?
I haven't paid for seatbacks at the stadium in the past. Looking forward to having them this year. I DID one time sit in someone else's seat when arriving to the game earlier than usual. It had rained earlier in the week. That whooshing sound was replaced by something more like wringing out a super soaked sponge. My butt looked like a 95 degree game during the 4th quarter. My wife, sitting next to the seat, was sprayed as well.
Do yourself a favor and bring a thick towel tomorrow. Maybe 2. You will thank me later.