Do you have a source for this? Where is it stated that one cannot overpay taxes for the purpose of getting a bigger return? Many people do this as a “savings” account as they’re not very good with savings so it sort of forces them to save since they don’t have access to the money.
I believe he was suggesting misfiling, as in under reporting income or overreporting deductions in order to generate a fraudulent refund, which you could then fix/repay in cash (but keep the bonds).