"Caroline huffily replied that regardless was a footless, weak word and got you nowhere, that on the other hand you threw in the word irregardless and won any argument hands down."
Dawn Powell, The Locusts Have No King
Dawn Powell, The Locusts Have No King
In places that use irregardless, I would view it as implying it is foolish to regard as opposed to regardless which often means foolishly not heeding. The fact that "heed" is missing from my spell check might explain why new intention distinctions were needed..