TitleWhat happens if a user does not have permissions to a list from another web application/site
I used a qListView to pull a list from another web application with a user that rights to both. When logged in as that user I can see the contents of the list from the other web application.
I then logged into as a user that only has access on the web application hosting the qListView. I could not see the contents of this web part because this user does not have rights to access the other web application.
This same logic applies if you were to set up the web parts with a user only have access to where the web part exists. So from site to site or site collection to site collection.
If the user does not have access to where the source data is being pulled from then they will not be able to see it even if they have access to where the web part is hosted.