... always have their knees really bent when they're pointing a gun while walking. I don't see other actors doing that and I tried it. Didn't work for me…awkward.
Is it just Hollywood or is there a good reason for that stance?
TBH, IMO, 'bout da only endeavors encouraging stiff/straight knees are landings in gymnastics (improper landings can be absolved) and board diving. Most other sports or daily endeavors I've been capable of conquering has involved flexed knees; almost always incorporating feet placement shoulder wide.
Although, must admit, nowadays, I do have to make sum (OK, maybe many) compensations.