As I'm reading your post, I find my mind wandering down two paths at the same time:
First, I've seen my share of issues that were lurking under the surface emerge, sometimes at the worst possible time (like when you are seconds from nutting in her!). From buried child abuse, to addiction, to massive debt, to trust issues and more, I've seen SB's who (seemingly) randomly decide to punish me for the past acts of others, including themselves. This, for lack of a better term, sucks.
But at the same time, I'm remembering that guy we all knew in high school or college. You know... the guy who was always banging the hottest chicks with minimal effort and then tossing them away with their used condoms. And they somehow managed to slip out of the inevitable drama unscathed. Then it's wash, rinse, repeat; all too often with the bestie of the last girl!
In college, that guy was one of my closest friends. I recall asking him one time after he had burned a particularly gorgeous babe (Cheerleader, perky boobs, great smile, wild child...) by banging her younger sister why he does it, besides the obvious. He gave me an obvious answer, of course: The crazier the chick, the better the sex.
I have tried and tried to put the lie to that claim. I have yet to do so.
Now if you've read my posts over the last few years, you know I have walked away from SB's once I see those issues rise out of the seas of the past. The hottest SB I've ever had (21, now 24, half Filipino, half Italian, 5'2, 96 lbs, D-cups and SKILLED) was molested by her father from ages 8 to 14. When I eventually learned about this, I ended the arrangement and told her I needed her to know that she is worthy of love from an older man without the need to have sex. And I still see her every couple of months now. We talk about her life, and I coach her on career skills, as well as serving as an acid-test for the guys she meets either on the site or in her personal life. Frankly it almost kills me since she is SOOO hot. But I just can't be the guy that perpetuates the sins of her father and destroys her sense of self-worth and self-respect.
To answer your specific questions:
1. I do not accept crazy behavior, but I do call it out gently and calmly. I talk about her behavior, never her "attitude." I explain what I will do if it continues, I never "tell her" what to do.
2. Vetting strategies? I'm not phycologist and I'm not about to try to diagnose anyone. But like #1, I do evaluate behaviors in light of my past experiences. If she seems to be heading down a path that spikes my Spidey Sense, I proceed with either caution, or I just GTFO!
3. Mitigation techniques? Like #1, I observe behavior and if I think it's problematic, I will set aside time to ask her what's up? Again, I only discuss observed behaviors, never attitude. never accusing, just mentioning what I saw and let her know how it affects me. Then I let her know what I will do if it persists and I ask her how I can help. It's all standard conflict de-escalation and resolution like all those corporate "team building" trainings we've all done.
But yeah, the likelihood is that once the crazy shows up hard, it's the beginning of the end.
Life is good
The Cat