This question has been discussed before, and I agree with someone who enters a system warning the admin to take precautions, i also understand when someone doesn't warns the admin (as long is no damage done), due to some stupid admins that call the feds for someone who is just trying to help out.

But for defacing to call the attention when something is not right, I do not agree with it at all...

Maybe try to reach the admins boss, or something, but not defacing it. ( agree with what NetSyn said about crimes in general...)

that's just my 2 cents, thou.