power cord directionality

OP made a mistake, umbilical carries AC, not DC...ma bad....

Gosh, thanks.
It's all so clear to me now...

....and fabricator of cable clarified how it was just labeled backwards.....as it has Neutrik terminations, testing would reveal, due to the grounding at the power supply end, if it was backwards......thanks to all for some helpful, some not-so-helpful, but always OPINIONATED,  answers.....I must admit I have learned some things on this site, both about equipment AND about personalities....

Now I wonder why was it even bothered to be  labeled since it only connects one way..... (?)

So let me understand. are you saying vibration can have a negative effect  on how electrons flow? If you shake/vibrate any wire enough, it is possible to change the position of an electron?

In my opinion vibration can have an adverse effect on a connection point of a wire.

example: if you have a low quality outlet the physical connection between the plug and outlet may not solid enough and you may have arcing. Also the more valuable precious metals used in the plating (gold/silver) may offer higher conductivity.