As stated in this feature request, we work agile and the tester gets new applications versions (almost) on a daily basis.
The tester does not know which objects have been changed/deleted. And does ...
good question Masha, thank you!
I think the tester has to have the end responsibility and TC would only suggest to update namemapping, based on the differences it finds during test run.
One way to display the differences would be to use marking on the places where TC would expect to find a control, but it is deleted. See the example here: Version 1 contains an input field "Bedrag", version 2 (which is released next build for example when using continious integration could be the next day).
During test playback TC could compare both screens and link the info to the namemapping prior to testrun (sort of like a internal pre-run test validation). When it sees differences it should be made visible (like yellow marking), and TC would to suggestion to delete (or disable) the specific input field from both Namemapping AND Testscripts (both Keyword and Scripts).
Of course this is ideal situation for me, it should be discussed / evaluated by other TC users as well.