power cord directionality


IF power cords do indeed have preferred directionality, and one is inadvertently flipped for a few hours, does it "harm"it?
128x128jw944ts
uhhh... duh end wif duh prongs on it gits plugt innuh wol. duh uther end innuh yer lektronix.  

how yu gonna ree vurs it?


didn't you miss few "mmm....like...mm...you know...mmm...like..."
by any chance?
IE:  ALTERNATING CURRENTThat is the key word!  Current alternates direction.  Yes, DC power does exist, and transformers are DC to keep from blasting everything with a 60 cps hum, but interconnects and speaker wire?   NO!   Think about it.  Current for a 400 cps signal, for example, goes back and forth 400 times per second.  It does not flow like water.  The current driven magnetic force pushs the speaker out 400 times a second and pulls it in 400 times per second.  It does not push and rest.  Directional wiring for alternating currents, such as for fuses, speaker, and interconnect wires, is pure witchcraft, i.e. fantasy.   If you do not grasp this, I have some magical, one direction, magiquark driven fuses for sale.  Call 1-800 One Muon.
When we talk about A.C. power or POWER Cords, there is no Physical science that specifies "polarity"

Polarity on A.C. power is mainly for safety. In the off position the device can be safely serviced because there is zero power after the power switch. This is why the HOT side of the cord is directly connected to the power switch. 
As for a device not equip with a power switch be careful.

U.L (underwriter labratories) is the largest testing facility in the U.S. tasked with safety testing things like power cords. I would venture to say that in this era, inorder to get the U.L. listing a device not equip with a power switch would require a polarizes power cord.