If you hadn't asked for opinions, I wouldn't offer my critique. But, you asked. :biggrin2:
I don't trust peepholes, or most peoples, for that matter. Tactics are basically just a matter of doing something effectively, but not necessarily predicable. So I don't stand behind a door, when a questionable activity has brought me to the area. Talk through a window, if you must communicate with someone.
Then, don't trust people you don't know. Your girlfriend was disarmed by conversation and empathy: "He noticed the gun at her side and understood her reaction to him knocking." This ignores the fact that he never should have seen the gun in the first place. By giving him the visuals, you've given him a few advantages. Not the least of which, is knowing you're prepared to fight, if needed.
Then, the worst thing she did, she went outside. I might talk to someone through a window because it might be a legit situation where someone needs help. But I'm not going outside my home for someone I don't know. I lose all my advantages by doing so. The person is welcome to call me paranoid, if they want, but it isn't going to be of any help getting assistance from me. If they need help, I'll happily call emergency services for them.
She made assumptions, without any means of confirming anything. Doesn't matter if we're talking gunfights or accounting, assumptions lead to all kinds of trouble.
And I say this as a fairly large guy, with years of training and more experience than I'd prefer to have under my belt. Doesn't matter! Tactics are tactics. Man or woman or 'other', you don't give up the high ground without a really damn good reason. A tow truck driver with a him-issue...not even a sorta OK reason for me.
What I tell people is simple and usually hits home: What would you have told your child to do?
That isn't a statement of somebody acting like a child, or being weak. No insult intended at all. It's simply a way of checking oneself. If you think it would be OK for your 8 year old to answer the door for a stranger at 1:30am and go outside with said stranger, then, alright. I doubt most people would think it's OK. If they can answer the question of why it isn't OK, then they should have all the reasons they need to heed their own advice.
It's a good learning experience, so long as she learns.