Which statement about state income taxes is incorrect?

The statement regarding whether state income taxes can apply to visiting nonresidents is indeed the one that is inaccurate. Generally, state income taxes are based on residency, and typically, a nonresident who is merely visiting a state wouldn't be subject to that state's income tax obligations unless they are earning income within that state. Therefore, it's common that states do not apply their income tax to nonresidents visiting without taxable income generated from sources within the state.

In contrast, the other statements accurately reflect the characteristics of state income taxes. For instance, states frequently align their tax rules with federal laws, in which case they may "piggyback" on the federal version of tax law. Additionally, states have the option to "decouple" from the federal tax code, meaning they can choose not to conform to certain federal tax provisions, allowing them to have independent tax regulations. Lastly, some states may offer amnesty programs as a means to encourage taxpayers to report and pay previously unpaid taxes without penalties, further demonstrating how states can have flexible tax policies to address compliance issues.