1. Merchant sets up Stripe account.
2. Merchant begins processing credit cards.
3. Stripe's vetting process kicks in and takes a look at Merchant, finding that Merchant is operating a business type that is prohibited by Stripe's TOS.
4. Stripe cancels all transactions and locks the account.
From what I can tell Stripe allows you to start charging immediately and only some time later does the vetting process kick in where a human takes a look at the merchant. When the merchant is operating a business that is prohibited[0], this happens.