The NEC has no control at all over how appliances are constructed.
Actually Bob there are those design issues in 422 and 440.
440.65 Leakage-Current Detector-Interrupter (LCDI)
and Arc-Fault Circuit Interrupter (AFCI). Single-phase
cord-and-plug-connected room air conditioners shall be
provided with factory-installed LCDI or AFCI protection.
The LCDI or AFCI protection shall be an integral part of
the attachment plug or be located in the power supply cord
within 300 mm (12 in.) of the attachment plug
422.41 Cord-and-Plug-Connected Appliances Subject to
Immersion. Cord-and-plug-connected portable, freestanding
hydromassage units and hand-held hair dryers shall be constructed
to provide protection for personnel against electrocution
when immersed while in the “on” or “off” position.
Newer vending machines also included.