Well, in Italy the "IRS" (Agenzia delle Entrate) is not allowed to cross-check banking statements with its own data from Tax Returns.

Whenever anyone proposes to allow it, the members of the informal "Party for Tax Evasion" scream and denounce the descent towards "Taxation Fascism". It's so pathetically cheeky, that it feels a bit endearing (how dare them, what rascals!)