yes. Maybe there is a gun off screen? How are you supposed to know the whole picture without being there?
I do not know the accuracy of this. I just learned the mishna in avos this week. dan lchaf zechus is for a muchzak kosher, but the Ra"V or Ty"T (dont remember exactly) said you do not have to see someone who's clearly doing something wrong with little evidence to justify it and assume the best.
dan lchaf zechus doesnt come at the chov of the person on the other end as far as I know