The idea is that you would apply a high voltage to just the cable, with nothing else attached. If it's just a cable, no harm no foul. On the other hand, if you start seeing smoke from the embedded electronics, you may want to use a different cable.
[1] https://e2e.ti.com/blogs_/b/analogwire/archive/2016/03/07/wh...
Maybe an innovative company could add warnings for USB ports that draw power but have no recognized device. For the advanced ports with charging support and so on they should have power monitoring already.