on accident

[RonButters at AOL.COM]

I just asked two guys from Chicago about this (one is actually from central
Micihgan, age about 30; the other is 40).

They are both aware of BOTH usages and seem to find a semantic distinction
between them: BY ACCIDENT means "unintentionally" in a broad sense; ON
ACCIDENT refers to some physical incident in which someone is culpible: BY
ACCIDENT I CAME ACROSS SOME FAMILY JEWELS HIDDENT IN A WALL but ON ACCIDENT I
TIPPED OVER THE DRINK.

In a message dated 1/18/00 12:48:36 PM Mexico Standard Time,
flanigan at OAK.CATS.OHIOU.EDU writes:

<< >I also asked about the "evaluation" of the phrase.  Most regarded it as
 >some form
 >of substandard.

 Even the ones who use it?  Assuming they're unaware of the other usage,
 this surprises me.
  >>