PACER would not cooperate with this. Also, the problem with automating it is that accounts require a credit card, so you'd have to give the automation script the ability to charge your credit card (if there's a bug for example).
I don't think the idea is full headless automation but rather some way of coordinating which set of new documents should be retrieved by each volunteer (until either their free limit or willingness to donate time runs out). Maximizing efficiency in this way would presumably increase overall coverage.
It almost strikes me as sort of like a torrent or something like Folding@Home. If everyone signed up to the service and provided their credentials (lets ignore the obvious security issues here), when someone requested a document via RECAP it could use the accounts that have signed up. It would use each account until it got near the $30 threshold and then move on to the next one.
