Unable to delete an account

[kivikakk]

I'm getting a 422 Unprocessable Content upon submitting an account deletion request.

At first I thought it was because the user[i_am_sure] field is submitted twice (once with 0 for the hidden field, once with 1 for the checked box), but upon removing the hidden field it still produces that output. (And indeed, on not checking that box, the error flash is correctly displayed.)

Then I thought perhaps the authenticate call was failing, but using an incorrect password produces the correct error flash too, so I'm guessing it's just being raised by @user.delete! for some reason. I imagine the error log will contain more useful information; maybe there's some delete that's not cascading.