When you work with Apex (or really any other technology bridge to the traditional financial world, Q2's Helix is common for traditional banking, Apex Clearing is common for stock trading, etc) they require you think about things like this during your implementation. Its not quite as turnkey as something like opening a Stripe account; your implementation will need to demonstrably pass a playbook of tests before your partner will allow you to play in real financial transactions - and those tests typically include things like account closure or program shutdown.

Basically, the traditional financial services partners who give startups access to these legacy networks know their clients are startups who might not fully understand the space or might want to cut corners. They're good at making sure they're protected against their clients' behavior, and in most cases legally the end users are actually the customer of the financial services company, the startup will be considered a "deposit broker" instead of a "bank" etc. Its been longer since I've touched the stock broker side so I'm fuzzy on the specific terminology but its similar there.