One trend I've noticed is that Js tend to be more about prevention, whereas Ps prefer to deal with problems as they come. The modbox is very interesting in this respect!
Yes, this is one of the best ways to distiguish the two.
To the OP, I know a more than a few ESFJs who will gladly start conflict. Actually, it's the Fe types I know who can be the most open to confrontation. I have two close friends, both Fe-doms(the guy is an ESFJ, the gal is an ENFJ), who have dated off and on for the past 10-years and have an elementary school aged son. We had to stop going out with them for awhile because they'd get into public fighting matches when we all went out as a group. They would argue, yell and carry on, no matter where we were. One time they got into a screaming match on a kayak! They've called it quits, but they reached out to each of us in our group before they did. They wanted advice, they wanted us to know how they felt, they each gave their side of the conflict, etc.
My grandmother is a stereotypical ESFJ, but she's also quite confrontational when she wants to be. She's also right in the middle of the drama in our family, and more often than not, she's had a hand in starting it. She easily builds and divides loyalties, and will "go off" on you. It's not beyond her.
I'm naturally accommodating, but I'm also very assertive and direct and will get into conflict to defend other people or myself. I like to have issues resolved when they come up, not later. I also believe that conflict can lead to growth and understanding. Conflict avoiders frequently exacerbate problems by putting issues off until later and sweeping them under the rug, delaying the inevitable. It's surely not always neccessary, helpful, nor appropriate to express your displeasure, and I most typically keep things to myself until I've worked out a peaceful solution in my mind, but I'm not perfect. I've never been in a physical fight, but I have seriously told some people off, something Fe would seem much better at than Te(??). Fe can embarass you, put you in your place, disconnect from you and turn others against you because of its focus on people and social dynamics. The one time I was ever suspended from school was when a friend of mine was being nasty to another one and I encouraged a group to send the offender a letter, telling her off. Granted, I was about 12 or so and my actions were immature, but you get the point.