I used to run a bar in the West Stand at Stamford bridge (Chelsea), and that used to be open only before kick off and at half time. Originally served plastic stubbies of Bud at 3 quid a pop (seriously, why would you bother...) until someone chucked one on to the pitch against Spurs, then they went back to cups.
You weren't allowed to take your cups up in to the stand either; cue mad swill to down as much as you could during half time.
It's just soccer though: I used to watch rugby out in Richmond, and they had Heineken servers going round the crowd using the "drenching packs" to serve beer to you in your seat. You could take spirits out of the bar as well.
I think sitting down drinking, away from the bar slows your consumption down, rather than standing watching the game where you have easier access.
The scum bags involved in this incident are more likely to have been using something from a backyard lab, or just have an extra chromosome each. Dangerous animals belong in a cage.