Silly Question: Short Power Cord + Ext. Cord?

If an expensive power cord is too short, would the use of a cheap 12 g. extension cord from the cord to the wall degrade the sonics? Are you the defeating the purpose of the upgraded cord?

The argument would be:

(1) The house wiring is cheap 14/3 stuff anyway, so doing this wouldn't really make the source of electricity any inferio.

(2) Above argument supports the belief that high grade power cords make their sonic difference through filtering, altering, cleaning of the raw AC. Hence, this would have no effect?

I've considered cords for sale that were too short, and wondered if this would be a viable solution -- or is this audiophile HERESY!