Honestly? I would worry too. Generally, the data connections in the form have to be updated to be directed to the new list / library. I wouldn't have much faith that a redirect would work. But perhaps they have a test environment already set up and have checked this?
Also, if you publish a form to a new location (which it sounds like the new URLs will be a new location, since they are changing), InfoPath will prompt you about updating the data connections and will auto-magically update the SharePoint connections.... so perhaps just a republish will be able to set things back to rights.