Comment 1 for bug 537351

As bank accounts are mandatory tied to partners, there is no way to create bank accounts without a partner object linked.
Apparently your bank provides you with an ID to match a partner with, so what keeps you from extending the logic with ID matching? This way there can be no mistake. You only have to make sure the ID is correctly parsed from the provided bank info...

I see four options:
1. Don't do anything. Hand link the right partner to the bank account and remove the wrong one. This is a one time operation per bank account.
2. Drop the creation of new partners and rely on hand work, either beforehand or from an error log (causing imports to fail).
3. Extend the mechanism to use smarter options available as the one mentioned. Should be a relatively simple addition.
4. Extend the error mechanism to allow wizard like creation of bank accounts. This is not an easy task.

For now, 1 works. My vote goes to 3. I think it should be easiest if you built this yourself, as all test cases are in your hands.