Indeed. Youtube generation just films it. I reckon that has its place as witness testimony, but did the guy filming help LE/prosecution? Maybe, if the instructor has it for his examples, but the first thing I thought was did the guy who was stabbing the other guy on the ground get up and threaten the guy filming or were they in cahoots? Seems you'd be in just as much danger there filming (like the guy who stopped to call the cops on the kidnapper and then got shot).
Tough questions everyone should be asking themselves about what they'd do, carrying or not.
I know that my personality is that of Responder/Rescuer. I know that for sure because I gravitated to that type of service work. First Lifeguard, then Volunteer Firefighter, then USCG SAR Aircrew. I stop for serious car accidents if professional help has not yet arrived, this terrifies my wife when she is with me because she does not want to see that stuff.
But for me, response is hardwired. So I have to be very very careful to watch out for knee jerk reaction and involvement. But so far I've been lucky to never have been at a serious event/altercation or worse. Part of it's where I live there is not much of an underclass of tweakers, homeless, etc. But it's also that we don't go out at night anymore... I've walked away from a number of fistfights, potential trouble, and the like. Drunks gotta be all stupid ya know. But there's no Maxx, no Bart, no bus lines.
We just had a shooting/suicide combo last night up at one of the low income housing developments. Guy got into it with his buddy, shot him (in the arm), then fatally shot himself. I'm surprised it doesn't happen more often... there is the underclass. My ex used to live in that place after divorce... pretty low. I wouldn't intervene for her no matter what!
The problem with third party intervention is that sometimes you don't know what you don't know, and this could change who the good guys and bad guys are.
I was working security at a club out by the airport. There was an altercation between a 50 year old man and a 20 year old woman. I was trying to get them to calm down. When the man shoved the woman, my supervisor came over from the other side of the room and threw the man out. What my supervisor didn't know was that the man had dropped a 20 and the woman had stepped on it and was refusing to let him have it.
In a progresive jurisdiction, you could be facing jail time if you use your weapon. I won't intervene unless the victim is someone I'm willing to go to jail, to keep safe.