I think in this case that the screws used on top were too fine a thread and not long enough.
I agree with your words of caution about the screws. I've seen them still hanging out the holes on several occasions and been very careful not to knock them in. I don't think this is a job that just anyone should try, and the Utility might have some strong opinions on that too.
Bill
Has anyone seen or heard of any Fires or Injuries that resulted from a situation like this?