The photo doesn't show anyone congregating down the front, not does it show how many were at kiosks or toilets. All it shows is the number of empty seats in a snap shot of the crowd at a particular point during the evening. The gaps are sporadic if you look closely.
The photo was taken towards the end of the first half (I am top left, and moved further down as soon as the half time whistle went). If that photo had been taken at half time people would be sitting down, some would have food and drink, and I doubt anyone would be waving a flag, clapping, or looking in the same direction.