Other states do this and even the federal government, I think. They're shooting themselves in the foot. If the path to legal possession is tortuous and likely to incriminate you then you're protected from divulging it and your nonpayment of taxes is wholly legal on the grounds attempting to collect makes the state violate the 5th.

The widespread use of parallel construction -- and even merely its plausibility -- means that the IRS's current stance on reporting illegal income is likely suspect as well.