Syntactic blending: bunker down

[Se�n Fitzpatrick]

My grandmother called these "malaphors":  mala(propism) + (meta)phore

>From "Jonestown for Democrats:  Liberals follow Gray into the big nowhere", by Marc Cooper in the LA Weekly http://tinyurl.com/qgfm (emphasis added)
  As the insurgency swelled, the best that liberal activists could do was plug their ears, cover their eyes and rather mindlessly repeat that this all was some sinister plot linked to Florida, Texas, Bush, the Carlyle Group, Enron, and Skull and Bones. By BUNKERING DOWN with the discredited and justly scorned Gray Davis, they wound up defending an indefensible status quo against a surging wave of popular disgust. 
"Hunker down" mixed up with some such phrase as  "go into the bunker with".
How can you test hypotheses about syntactic blending?  They are common in bureaucratic/business speech and writing, but investigation is a delicate matter.  People I've questioned haven't known where they got the phrase.  Some were scarcely aware that they had used it, some became indignant at having their wordsmithing remarked upon or irritated at not knowing where the malaphore came from, and a few have conceded they had probably confused a phrase or two.
Seán Fitzpatrick