Clean up when closing a terminal

I've taken to clearing my ssh-agent identities and sudo timestamps when I close my shell, by putting in my ~/.bash_logout file:

if [[ -n $SSH_AUTH_SOCK && -z $SSH_CONNECTION && $SHLVL = 1 ]] ; then
 ssh-add -D
 sudo -K
fi

One caveat: the above only works using the shell's exit (or logout or Ctrl + D), not with iTerm2's close button.  However, that can be fixed by using an exit trap in .bash_profile instead, like so:

clearKeys() {
 ssh-add -D
 sudo -K
}
if [[ -n $SSH_AUTH_SOCK && -z $SSH_CONNECTION && $SHLVL = 1 ]] ; then
 trap clearKeys EXIT
fi

To be clear, the latter version requires no changes/additions to .bash_logout.

Rationale: I usually work on a desktop, and keep a copy of my work in sync on a laptop using unison.  Making the SSH connection from the laptop adds the key to the session's ssh-agent, but I don't want that to persist after sync is finished.  I don't want keys to stay active while I'm not planning on using them soon.