bar codes and how they could be used better/easier

going to a concert the other night I had taken a piece of paper with a bar code on it. This got scanned at we were allowed to enter.
I would love to have this applied even more to other parts of life. Especially for small purchase items eg train tickets, papers etc. They have tried this with coke bottles bought via the mobile phones, but would love for this to be extended. Either just purchase it or provide a bar code to scan at a scanner.

Now this could mean that you buy more than you want, but i guess if they are only small items then it's not so bad. I like this better than a stored value card that you recharge, the main reason is because phone's now can connect to the internet, and so you could just go on and recharge yourself whenever you want v's needing to access a store.

Do you see this happening soon ?