In this case, the business with the risk is the bank lending the money through the credit card. And credit card purchases made just before declaring bankruptcy are highly scrutinized as potential fraud. Paying the lawyer with additional debt you're attempting to get discharged would seem to fall under that category. As a result, in practice, you won't find bankruptcy lawyers accepting CC payments from their clients. If they accept CC payments, it must be from someone other than the client. (family, friend, etc.)

Given this, there is no reason to price the risk (a customer paying their lawyer with debt that will be discharged) into their pricing: it is already prohibited by statute.