Infinite Batteries?

I was listening to a Bill Simmons podcast today where he was talking with Nathan Hubbard of Ticketmaster.  A major focus of their discussion was how event entertainment was changing since people can get great experiences while watching from home on their huge HD televisions/sound systems. They both seemed to like not just using phones as tickets (making it pretty impossible for scalping without monitoring) but also using the smartphones during games and concerts to access additional stuff, like player stats. 

And I have just one question: do these smartphones have infinite batteries?  I get nervous having my phone serve as airplane ticket (tried it once thus far), as the phone can start losing power pretty quickly.  I guess the new stadia might have power-jacks everywhere.  Otherwise, we are going to start carrying spare batteries around, just like the average soldier of the US, Canada and other advanced militaries. 

I see their point, but unless smartphone batteries get much better fairly quickly, I am not sure we can turn every event into a smartphone-compatible experience. 

Otherwise, an interesting podcast about what technology is doing to the event business.