People are stupid. I never sign up for auto-pay. I auto pay from my bank though a check to them, not from their side pulling from mine.
You know more often then not that auto pay your bank sends out is a "draft" which is a paper document having your routing number and account number on it.
Should a company with that information claim a prior business agreement or a debt owed they can send in an ACH payment request (what most people call an auto payment) and your bank will pay it. You will be left with the money gone having to take your time and energy trying to get the money back.
Fed reg E does not provide you much protection, specially if the dispute goes over 60 days, in which case your out the money unless you go to court.