I agree with the doubt about the "insurance salesman". I had a break in service after my second tour in VN and sold insurance for a while. One of the first things my agancy manager told me when I started was to get a new car. As he put it, "You can never be a successful salesman if you don't look successful!" So from the description your wife gave of this guy, I seriously doubt if he was selling insurance. I would be more likely to think he had some other, most likely illegal, reason for being there. The advice to NEVER open the door to a stranger should be carved into everyone's forehead. I won't do it and I'm a pretty big guy (6'3" - 265) and I'm ALWAYS armed. If they have anything to say to me, they can say it through the door.
I made up a sign that I wanted to put on the front door, but my wife won't let me.
It reads:
WARNING
TRESPASSERS will be shot on sight!
SURVIVORS will be finished off slowly and painfully!
SOLICITORS will be gut-shot and left to bleed to death!
I thought that would get my idea across plainly enough, but she didn't agree, so it hangs above my desk.