I used to be able to disable iTunes by:
$ chmod -x /Applications/iTunes.app/Contents/MacOS/iTunes
But then apple made it harder:
$ sudo chmod -x /Applications/iTunes.app/Contents/MacOS/iTunes
chmod: Unable to change file mode on iTunes: Operation not permitted
My objection is: Apple starts iTunes automatically, if opened and not signed in (with the sign-in dialog up) it blocks restarting (I have to force kill it) and when XCode updates, iTunes needs to be closed and it also isn't able to exit, and I have to force-quit again.
I don't know how Apple is able to deny the "sudo chmod"
I'm looking for ways that still allow me to run it when I need to.