There are many good reasons for NOT having programme notes. It drives me crazy to see faces buried in booklets when ears and minds should be absorbing the music. It's much better NOT to follow every word or note, but instead open your heart and mind. Familiarity will come with time. Never miss the opportunity to engage with what the performers are expressing. Programme notes can encourage lazy thinking and lazy writing too, for that matter (unless the notes are by the composer or someone who knows the subject well enough to have something useful to say, in which case they need to be preserved.)
In theory programme notes (and not just the BBC's) should be a way of enhancing the musical experience. In practice, programme notes are often "filler", so superficial as to be downright misleading. Sometimes I've read things by people who clearly haven't even heard the piece they're writing about, and chunks of material borrowed without attribution. They can get away with it because programme notes are ephemera, designed to be, like their medium, discarded and often unread. Most programmes exist so promoters can sell advertising.
But notes should serve a purpose. When people have taken the trrouble to come to a concert, they deserve some form of extra enlightenment.
During a recent Prom, a friend overheard a conversation at the first interval. "Is it over already?" some tourists asked. "We don't know what this is is about but WE'RE QUITE ENJOYING IT". I thought it was wonderful that they could be so open-minded that they could approach Wagner and get pleasure from just listening. They were exactly the sort of listeners we should encourage. In their case, telling them to look at programme notes would be a mistake. Rather, it would have been nice to talk to them about how they felt and why the music was so exciting. "Wait til the end", I would have said. "Everything goes up in flames ". Capture people's imaginations and they can sit through six hours of singing in foreign, Or kill their souls with lousy advice.