In this particular context, a "non-conforming" cable would cause troubles by starting fire or dropping voltage below usable range, not by limiting charging current. The only sane thing to do with such cables is to throw them away.

Really, we're talking about physically broken cables here. As long as there's electrical connection, there's no other way for a cable to not work at 3A/60W with USB PD. Its cable requirements only start when you want to go higher than that - and 60W is plenty of power already.