Thieves want to work to empty that new account as fast as possible. And they still can't without suckers who volunteer to run a "check-cashing business" or similar scam.
Because banks are held responsible for fraud (from consumer accounts), they work hard to never be the ones holding the bag, so they put up roadblocks in attempts to engage in irreversible transactions. If you say "hey, I opened my account yesterday, now I want to withdraw the $40,000 that just showed up in it, 10's and 20's please" they will nod politely and call a bank manager.
