What I found mildly amusing about the episode on Sunday evening was the pointing of telescopes at the sun in daylight, when for years Sir Patrick has warned time and again about the dangers of looking directly at the sun with the naked eye, such a during eclipses, and also through binoculars too. Yet here they all were pointing a telescope straight at it! Not sure I heard any warnings? Okay so they had a filter across the lens, but might some people be tempted to use something not suitable and endanger their eyesight?
I reckon they'd be more likely to leave the finder scope on and feel an unpleasant burning sensation on their neck as they peer through the eyepiece.
Seriously though, if there is even a pinhole in your filter you would be in trouble, and although Pete Lawrence mentioned in passing that you should check it before every use I think that should have been emphasised more. Everything except light bulb filaments should be completely black when you hold it up to the light.
Even then I don't see a big advantage over just projecting the sun onto a white screen, completely safely.