Arguing that the less trained are not more likely to have holstering, or drawing negligent discharges than professionals, is like making the argument that because one person dies wearing a seat belt (and thousands others are saved by them) makes not wearing one sensible.
My point was that newbies are likely to be super careful as they are not yet comfortable having a gun on their person, whereas a police officer or someone who has carried for years might well become onchalant about it and get careless. I recall how much I thought about printing, or about raising my arm which might expose the weapon, etc. and now, to be honest, I go about my normal activities without much thought about the gun on my belt or in my pocket. Sitting down on a toilet, however, always reminds me of the need for a bit more care.
Accidental or negligent discharges virtually always involve someone having their finger on the trigger when they shouldn't, or having something get into the trigger guard while holstered, or so it appears to me. When I carry, usually pocket carry with a pocket holster, nothing goes into that pocket besides the holstered gun. Not even a tissue or a piece of paper with what I need to pick up at the grocery store. And I never put my hand into the holster unless I am concerned that I might have to draw the gun within moments. I really do not worry about an accidental discharge.