Thanks for the reply. That's right, if you use SVB you have the fund payroll through a wire transfer. The wire can come from any account (including an SVB account). ACH won't work.
I also agree with the other commenter downthread that this is adding an unnecessary layer of complexity, but I understand why you might be doing it to avoid overdrawing an account that has been emptied. Still, I'm not sure this default opt-out is the best solution - maybe it would be better to ask those who did move money out of SVB to cancel their ACH schedule, rather than unilaterally ceasing ACH processing and asking those who didn't move money out of SVB to change their method of payment.