The problem isn't getting served, its whats being served.
The problem is getting served at half-time. Clearly that's always going to be a problem in a football ground - I accept that - but just how early before half-time should you have to leave in order to be able to buy something at half-time? On the basis of Friday night in the WSU, I think you'd have had to have left your seat between 30-35 minutes to have any chance of being served.