Zelle at major banks already does that. I can't transfer more than $2k-$5k into my own account of many years at a different bank, and I'm pretty sure the limit was more like $500 initially. Honestly, I have no idea how to steal $50k from anyone's banking app. Maybe a wire? Haven't tried via app. Not to mentioned whoever you're wiring to has been KYC'd. But certainly not through Zelle at US top 5 banks.