on accident

[P2052 at AOL.COM]

I've never before heard the phrase, "on accident," which sounds quite strange
to me (a lifelong resident of Alabama).   I must admit, though, that in
situations for which I had no frame of reference, I would analogize the
linguistic form and/or context to others for which I did have a token.  "By
accident," thus, may simply have been analogized to "by chance"   (at least
in my case).   In fact, I probably would have rejected "on accident" because
I could not readily identify analogues (even my repertoire of idioms and
collocations).
                                PAT