As a percentage, I'm calling 2%

I'm guessing the number will be closer to 2 than 2%.

What is the overlap of "people with enough money and interest to go to the super bowl", and "people who know how to sniff open wifi, and actually bother to", and "people who would bother to at this event"?

I mean, I know how to sniff wifi, putting me I suspect in a already small portion of the general population. Even so, I haven't bothered in years; I have better things to do. Sure, some people may sit in coffee shops and do it for monetary gain, but will those people be buying superbowl tickets?

I wouldn't be surprised if 2% of the crowd at DEFCON was sniffing the wifi at any point. But at the Superbowl? People don't bring laptops to the superbowl.

I think that is wildly optimistic. I'd be surprised if 2% were not drinking, though there may be some overlap.

The only thing more dangerous than bored hackers is drunk bored hackers.

Bur seriously, with only 11 minutes of action in a 3-hour event, 2% may be realistic.

The 11 minutes number assumes that you don't consider the formation (and constantly changing formations) before the actual play is run to be interesting.

Although the Super Bowl isn't known for attracting "true" fans, I would hope that "true" football fans would appreciate the intricacies that take place before and after the plays are run.

Edit: And honestly you think 1,400 people are going to be trying to sniff the WiFi from within the Super Dome?