Spring comes, and the issue of batch tokens raises it's head.
The problem is easy to solve in principle, once people analyse it correctly. It has learned to open the file before reading it - or rather, programmers have learned to allow for that. The system has actually taken the second approach, checking every access, so performance cannot be such an issue. If its automated, the security is gone. Just like processing time, research grants, or whatever, batch jobs should be given a limited amount of resources.