Spoilers on TV

Why do they give away the end of programmes on TV.  There is a programme on tonight called Fake or Fortune which looks at diffent pieces of art and then decides if they are real or fake.  Why does the BBC News broadcast this morning the result before the programme has even been broadcast.  What is the point.  It's the same when it comes programmes which finish with a synopsis of the next weeks programme.  No need to watch when you see this.  Then there's the programmes, normally on ITV which constantly go over what has been already shown.  The National Trust programme with Michael Buerk was some of the workst television I have seen.  Constant recaps, patronising commentary and 20 programmes when one would have done.  What is happening to the quality of entertainment being pumped into our homes.  The BBC still produces, on average, the best programmes in the world because their is no commercial pressure.  Let's make sure we keep the TV licence but please stop the spoilers