journalistic code: correcting mistakes in quotes: recommended or not?

or isn't this frowned upon anywhere anymore since it's in such general use nowadays?

it's Kentucky.

as a general rule it's fine to correct quotes in the manner you describe, but "seen" adds something to this story

Here they have Kenneth Lay as an eyewitness! He's not dead!

http://www.wlky.com/news/13547817/detail.html

"and she didn't have no legs"

Personally I'd leave it as it is. Otherwise CNN could get a lawsuit for twisting her words around. ;-)

Isn't (sic) the normal way of handling this?

Dan, "isn't" is spelled correctly.

wouldn't (sic) be just as distracting, though? or maybe not if you just place it after the first "i seen" or whatever.

(sic) may have had honest intentions, but it reads as "and here is what this illiterate git said (or wrote)..."

I've never seen sic used outside of spelling or punctuation (incorrect or archaic). Colloquialisms, particularly those where you're transcribing someone's words directly, wouldn't get 'sic'-ed.

illiteracies in quotes aren't "mistakes" but what the person actually said and shouldn't be corrected. OTOH tangled syntax should be clarified for the readers comprehension tho it's a slippery slope.

I was taught to correct or 'tidy up' poor grammar unless you either want to add colour to the story by reporting real speech patterns or you wish to make the interviewee look stupid.

People don't speak in complete grammatical sentences: that's just how spoken language is. Most of the time, however, they probably believe they do, so altering 'I seen' to 'I saw' is probably closest to what they thought they said.

(sic) may have had honest intentions, but it reads as "and here is what this illiterate git said (or wrote)..."

Yeah, it makes me think of some Sunday tabloid story about Ian Huntley's letters from prison or something. "Incoherent and riddled with spelling mistakes..."