Are people afraid to interfere with a robbery or such?
If you know the "rules", then you know we can only draw and fire if we feel we're in imminent danger of losing our life or sustaining severe bodily injury. Most states DO have a "third party defense" clause in the carry regulations, but I'd go real slow applying it. You must be DAMN sure of the circumstances. Is the scruffy guy in dirty jeans holding a man in a business suit a mugger or an undercover cop making an arrest? You see what I mean...
There's a fine line to walk when "interfering" in a robbery or other crime.