Is there evidence that "most" new covid patients did not take precautions, or evidence that they got sick despite all precautions?

No one can get sick despite taking all precautions.

ALL precautions would be:If you have not been out of your house since March 1st, when items are delivered to your house you wait 3 days to touch it, you have seen no one within 20 feet since March 1st = YOU CANNOT ACQUIRE THE ILLNESS because you are not in a place that the virus exists.Most of us don't go to this extreme...  the less precautions you take the more at risk you are:- protesters/looters wearing no mask and maintaining no social distance = HIGH RISK- especially because they come from environments where virus is more prevalent == high density.

The problem is that no one can pinpoint exactly when or who they got it from.

Most got sick because someone else did not take precautions.

Most did not get sick because they personally did not take precautions.

Most did not get sick despite all precautions.

The virus is spread mostly through the air, not the hands or other surfaces.  Hand washing, sanitizing surfaces, etc., doesn't help a great deal.

The most important precautions are staying home when sick and keeping mouths and noses covered at all times.  However, these precautions don't protect the person who takes the precautions.  They protection everyone else from being infected by that person.

I can't cite anything definitive just yet but generally the issue seems to be those with chronic health conditions were directly exposed during treatments.

In other words, old dude with lung cancer comes to see his doctor who just felt up a COVID guy who got it from somewhere else. Now lung cancer old guy gets it and dies. Again, I don't have the numbers but from heuristics and case studies the variable seems to be underlying health conditions. And I think it's not entirely the underlying condition itself but the institutional settings they are exposed to that gave them contact, despite the best attempts at precautions. Last I heard in normal times getting an infection in a hospital, i.e., dog poop remnants on a scalpel, even in the best cleaned hospital was more than 50%.