I didn't quite understand the whole concept. The idea in Schuko plugs is that you cannot pull the cable out of the plug. It's totally fixed (either inside solid plastic, or attached with a strain relief that fixes it).

edit: now that I think of it, Schuko plugs of the install-yourself kind where you can attach cable with a screwdriver (not solid plastic with the cable) are done so that the earth cable is longer than L/N are inside the casing.

So are the British plugs. Perhaps pulling the cord out should be called an extreme failure mode?

(It was probably more useful 20 or more years ago, before moulded plugs were common.)

Most combination Schuko/French plugs I've seen recently are even designed in such way that when all wires are same length then the PE one has larger slack inside the plug.

Right, that's what I meant (i.e. the earth wire sticking out of cable end is "unnecessary long" if it is the same length as L/N).

However, it is very unusual if the cable comes loose from the plug casing.