This thought seems pretty much stolen from my brain :-)
Indeed, I can second that "(bad) security analogies are a pet peeve of mine" too. I made fun of them repeatedly on my blog.
And here is a really cool way to short-circuit this, proposed by the Risk Mgt blog:
"Security is like an analogy. It only works up until the point that someone considers an angle or aspect that you haven’t previously considered and accounted for."
This is soooo cool indeed!