Fair enough, I'm not very familiar with the details of that case, but my overall points are that 1) it's easy to remove traffic signs (and thoughtless kids prob

Fair enough, I'm not very familiar with the details of that case, but my overall points are that 1) it's easy to remove traffic signs (and thoughtless kids probably do it every so often as a dumb joke), 2) this can definitely lead to bad accidents (with human drivers), and 3) the legal system will likely at least consider whether the people who tampered with the traffic signs are culpable for the accidents.