System could (in theory) do the heavy lifting with the bar codes though. As currently I presume it'll check whether the season ticket is active or not.
Could issue the same barcode for the next season if the person renews etc.
Could then also in theory allow season ticket holders to buy games not included in the season ticket, like European games for example and use their season ticket to gain entry to it as the barcode could be added to the "active list" for that game.
Will depend on how the system is made though. Its likely setup the way it is because it keeps it simple. The more complicated something is the more expensive it becomes to buy but also for supplier to update and maintain.