I've been to a few games this season (including the AFC championship game, which seems like such a distant memory now!). I haven't tried the Wi-Fi lately, becuase it's always been restricted to Verizon subscribers (and IIRC dish network as well). But I did try it at the first game I went to this season, just in case something changed in the offseason, and it still took me to the login page where you've got to enter your verizon account number.
It really pisses me off, too <gets on soapbox> becuase these sorts of exclusivity deals are exactly what's wrong with the entire telecome industry, IMO. Stadiums are mostly financed by the public and wireless carriers use wireless spectrum which in my opinion belongs to the citizens just as much as our land, air, and water (or any other national resource). I realize that the Broncos pay to lease the stadium from the local governments, and the wireless carriers pay for their spectrum when the FCC auctions it, but I don't think they've paid the true market value in either case. And that doesn't absolve either organization from a certain responsibility to the public interest, at least from an ethical perspective (on a legal level, I'm sure they've got their ducks in a row and there's absolutely nothing wrong with it). Or perhaps my issue is not with the Broncos and Verizon, who are corporations doing whatever they can to make a profit, but with the government's oversight of the public interest. There are very strong arguments that the public interest hasn't been fully served in regards to either spectrum and stadiums, but I don't want to get too far off topic here so I'll leave it at that.