The Most Haunted pentagram-construction game did not result in the opening of the gates of Hell, nor did the UK get sucked into spiritual oblivion. They didn't complete the figure, they didn't return to their starting point. Maybe it wouldn't have done anything anyway, but it was a bit of a risk in my book.
The show found a couple of interesting things. I'm assuming there's no TV-style jiggery-pokery going on, but I have to always consider that as more than just a possibility. Assuming TV people are honest (no sniggering at the back, please), there were one or two good showings. A table moving with some violence (easily faked) and a few things thrown (also easily faked). That's the trouble with TV. Everything can be faked. A real event can be very hard to prove, when everyone knows TV can make anything convincing. Still, they did come up with some interesting bits.
If there's one lesson to take from that programme, it's this:
If you're going to ask a spirit to 'throw something', don't be in the kitchen. Nobody was hurt, but the knife looked very sharp. I don't know if that was genuine but I do have to consider that a faker might choose something less deadly to throw into a group of people in the dark. It might have been a plastic knife, of course, but then they'd have to synchronise a real-knife sound effect when it landed. Difficult to do on live TV.
So that might well have been genuine, if only because the item thrown was so dangerous.
I'm just happy they didn't finish the pentagram. I hope nobody else tries it.