Silent hang if SSH has issues - pass messages to user?

My duplicity commands were hanging after I changed the server IP (but not the DNS name). I could still get to the server via SSH so it took me a bit to track down the problem.

Since the host IP had changed, SSH threw a warning and asked for confirmation before proceeding. Using SSH I can easily see that and accept (or correct the issue). Duplicity hung silently, so it was not obvious what to do.

I think displaying the warning to the user would be helpful so folks aren't tripped up by this. As it failed silently, I only discovered it because I was monitoring the backup cron job, and noticed backups had stopped happening.