I was watching a documentary on TV last night about Extreme Television. Shock! Horror! Yuck! And I mean, really, some of the things on it were pretty bloody nasty. The reality TV show that tries to induce heart attacks in its unsuspecting victims caught my attention, for instance - some unlucky unemployed woman was hired to look after what she thought was a woman in a coma, but was actually an actress playing an abused wife drugged and chained to a bed by her psychopathic husband. The really sad thing was that when the 'husband' turned up, threatening the victim for considering the wife's pleas to help her escape, the victim was, as well as crying and begging, shielding the 'wife' with her arm. It wasn't a very effective defence, but the poor woman was trying to protect her. That's incredibly brave, and she really deserved better than death threats on national TV.

A couple of the extreme scenarios, though, have raised some questions that I'd really like to hear people's views on. First off: SCARE TACTICS.

This is an American TV show that sets up its victims in horror-movie scenarios (quite inventive ones, really, and not as nasty in handling as the show I was talking about above). The example I saw, the victim had good reason to think a lunatic was about to kill him with a hammer. Now, not unnaturally, he was pretty frozen with fear. But here's a thing: not everyone freezes when they're frightened. Some people attack.

A friend of mine, for instance, was washing dishes in front of her kitchen window when her boyfriend, evidently in a puckish mood, leaped up on the other side yelling 'BOO!' Without a split-second to think about it or realise who he was, she punched at the scary face as hard as she could. Her hand went right through the window, cutting itself as the glass broke; her boyfriend had to help her bandage it. Her instinctive response to defend herself was so strong that she actually injured her own hand. And that was in the safety of her own home, when it was just her boyfriend teasing her.

So posit the following scenario. Jo, a young woman with no history of violence, is set up on a scary reality TV show. She's confronted by a big man wielding a hammer, acting like he's going to kill her. In genuine fear for her life, and without having time to think about it, her hindbrain kicks in, adrenalin floods her system, and she leaps on him, grabs the hammer, and, before the producers have time to dash in and stop her, bashes him on the head, killing him instantly.

Who's to blame? Personally, I'd rule Jo out - if she had every reason to believe she was in danger of being murdered, it's basic self-defense. But what happens if the dead actor's family then decide to sue the show? Can the show argue that he should have known the risk he was running when he signed up? Or that it's the fault of his performance, that if he hadn't been quite so scary, that if he'd stayed out of reach a little more, he would have been okay? Would a court rule that the show had violated workplace health and safety by setting up dangerous situations? What do you think would be a fair outcome?

Here's another one. There was a celebrity makeover show, where people underwent cosmetic surgery to make them look more like their favourite movie star. Now, surgery has its limits: I might wish I looked like Julia Ormond, but while a surgeon could have a go at increasing the resemblance, the basic framework of my face and body is wrong. I'd just look like a woman who'd had a lot of surgery.

But supposing cosmetic surgery was much better, I'm talking science-fiction-novel good. Supposing, if I wanted to, I could undergo surgery that made me look exactly like Julia Ormond. And suppose something else: that Ms Ormond wasn't happy about that. That she didn't want some stranger going around looking exactly like her.

Could a movie star patent their face? After all, they can insure it: along with their talent, their face is their fortune, and the insurance thing suggests that the law recognises that to some extent. Come to that, could anyone patent their face? I can think of other reasons why it might be a good idea, the primary one being that an exact resemblance opens the way to fraud and identity theft if used by criminals. Plus, it's a pretty freaky idea; I don't think I'd like to have somebody wandering around with my face (assuming anybody would want it - and I suspect that if they could look like Julia Ormond instead, I might be a bit of a second choice). On balance, I think I'd support a face-patent bill; not necessarily anything that outlawed saying 'make my chin a bit more like Marilyn Monroe's', but a bill that ruled out imitating someone's entire face, I'd be fine with. But do you disagree - are face-patents a bad idea?