Would that include something like a poorly written
widget for the app formerly known as Konfabulator as
well?
Probably, yes. Anything that accesses iTunes as a COM object will cause iTunes to start up seemingly by itself. Although newer versions of iTunes have seemed to be a bit better in this respect in at least some cases... Sometimes, iTunes still starts up, but it doesn't display the GUI until you manually start it.
Point is that in order for any program to connect to iTunes, iTunes has to be running. If iTunes is not running, attempting to connect to it will trigger it to start. That's just a consequence of how DCOM works.