I think they interviewed the guy and he said that they were a group of avid bikers that always rode their bikes to the games. For avid bikers the four mile trip probably was not very long, but since the temperature was in the single digits I give them credit.
At the time I saw the bike it was leaning against the rail seen in the still photos. I thought the guy was in a nearby porta potty because smoke was coming out the vents. If the bike was that expensive, it was probably locked to the railing and I did not see the lock. Maybe it wasn't locked up and he just asked someone in the SWAT vehicle in the background to watch it for him.