Code sometimes makes allowances for situations which aren't ideal, as long as they aren't deceptive or creating a false sense of security.

So if you have old two-prong outlets in your house from back when, those are allowed.

If you replace them with a three-pronged outlet which is ungrounded, that breaks code.

If the three-pronged outlet is a GFCI outlet labeled with NO ELECTRICAL GROUND, that is allowed.