I can (kind of) speak to that question to Cape - from the handful of Pats games I've been to in the last 3 or 4 years, they've all been good experiences. Sure, you get a couple overserved folks in the stands who get a little louder than the rest - but that happens at pretty much any sporting event. But whether in a win or a loss, and regardless of the opponent (even vs the hated J-E-T-S) the crowd is generally friendly towards eachother and fans of the opposition...
The first year I had tickets was the last year of the old Foxboro Stadium and that place was a total slaughterhouse. 80% of the place was insanely hammered and there were half a dozen fights in each section, every game. By the end of the year, and after we saw a guy's face pretty much turned into bloody mush by a full kick from the row behind him..... my wife no longer went.
They won the SB that year.
The following year, they moving into Gillette Stadium and Kraft took the opportunity to make the stadium much more "family friendly" and security starting cracking down on super drunks and fights.
The following year, they won the SB.
The year after that, they won the SB....
as a result, the waiting list for season tickets ballooned to, last I heard, 65,000+.... That gave the Krafts MORE than enough leeway to basically completely clean the place up. You fart the wrong way in Gillette Stadium now and you're season tickets are GONE. They have 65,000 people waiting to snatch your tickets up so there is a complete zero tolerance policy at the stadium now.
Are some people over-served? Of course... you can't eliminate those people completely and you never will... but it is NOTHING like the old days.
As a matter of fact... there is a very likely chance that I'll be bringing my 7 year old to the game Sunday. He's a huge Pats fan (mainly because he's not a complete moron) and has already been to a couple games. He might not have a chance to see Brady/Manning on the same field again.
Could he hear a couple F-bombs? Probably but I have NO real concerns about taking him to Gillette.