My suggestion is to compare Tesla accidents per mile to non-Tesla accidents per mile. If people are being lulled into a false sense of security by AP then this should show up in the data.
You also add a whole bunch of other confounding factors if you're not comparing same-driver accident rates. Accident rates vary by location, city/highway driving mix, driver attributes (age, gender, credit score, etc), and probably many other things that may be correlated with Tesla ownership.