Require ALL extension cords to be rated for the full current of the circuit and outlaw 15A receptacles on 20A circuits. That way there is no need for fuses or anything.
In Europe there atre only 1mm2 and 1.5mm2 extension cords, both of which are rated for 16A when in free air (i.e. not buried in walls). Only Euro plugs rated 2.5A can have smaller cords, but there aren't any extension cords for those.

One issue might be the US wire size. 16AWG is a bit small for 15 amps and 14 AWG asomewhat beefy for general purpose extension cords.