\_ Because you're execing ssh-agent you're no longer going through the bash
\_ shutdown stuff when you log off.

But shouldn't bash obey normal bashisms when it exits, regardless of
how it's called?

My trick:

tcsh%  ssh-agent -c > ~/.ssh/agent  # as needed

# line from .cshrc, or by hand:
source ~/.ssh/agent

Of course, this is limited to one instance of agent and doesn't probe
it for reality, but it's not like I'm expecting non-GUI unix programs
to die all that frequently.  :-)

FWIW, the most useful stuff I've done is to throw it post-actively
into my window manager so that the shells it spawns (which is a fair
number over the course of the day) get the magic.  sawfish rocks.

David