I'll ask while I have the logs visible...

Often right after I make a wifi connection the tablet immediately begins downloading. My proxy logs show requests to repository.maemo.org and catalogue.tableteer.nokia.com. I looked around and found that the URLs appear in files under /etc/hildon-application-manager/ and /home/user/.hildon-application-manager/ contains some related files.
Then I got lost in the gap between bringing up a network interface and what seems to be a GUI application. If there was some configuration setting, I missed it.

What can I do to prevent these downloads?