Anyway, at my site I’ve posted an exposition - my take on the question of courtesy and communication. It is under the KD link, then Airplane Etiquette. (I’d embed a direct link, but as a guest here I don’t want to pimp the site.) In short, I agree that personal communication would be best, if only it was effective.

Overall, I consider KD a device that is akin to a latch on a bathroom door. That is, while people should knock, too many don’t. So, a latched door is a defense against someone opening the door without first knocking. And, that is why I agree with Dan that (as the product name suggests) KD is "defensive".

(Apologies if my HTML coding does not work here.)

That said, a funny part for me is the title of your blog entry. Now I can say that, beyond the positive product reviews, Knee Defender has also received sociological analysis in a book entitled “Life’s Little Annoyances” and an essay entitled “Normalising paranoia”.

It should be noted, perhaps, that my product is not one of the “little annoyances” of the book, but (the author indicates) an item that falls under the book’s subtitle, “True tales of people who just can’t take it anymore”. And, even that is somewhat off - though “revenge” is a favorite peg of the press.

As a gene-pool-driven inventor I’ve found that, while someone else’s annoying conduct can inspire the problem-solving cogwheels in my head to start turning, the dominant primal urge is to merely find a solution for a vexing problem. Once I get to the “Yes, that works” stage, or even just, “Yes, that would work”, I have gained a satisfying (if (then) non-remunerative) reward.

Better still, they could have a progressive seat spacing arrangement, e.g. seats got progressively further apart the further away you got from the emergency exits (which were also far apart). Safer and you could probably pack passengers in even more closely once you took passenger height into account.

Unfortunately, when Virgin noticed people preferred the emergency exit/bulkhead seats they had the bright idea of pricing them higher, hence ‘economy plus’, which puts money ahead of physiology.

My strategy is to engineer the possession of a close relation who happens to be a member of aircrew. I then get to fly business class for half the price of economy class. NB Don’t get too envious though. The last time I exploited this was in 2001 on a transatlantic flight. You have the priority of freight, which means a lot of waiting in departure lounges and ad hoc sleepovers trying to get the heck out of the US when the flights are all full.

I like this idea of individuals imposing their own constraints on the technology around them - stuff like slave-flashes to prevent speed cameras reading number plates (or even the apparently legal angled transparent cover fitted to the early 1990s Lotus Elans - see here - image from Pistonheads).

Of course you’re right Crosbie that most so-called security is merely security theatre, but sadly it’s a production we were not given the chance to decide whether we wished to attend.

As for our ‘culture of fear and paranoia’ you do realise that a lot of the related ‘heightened security measures’ aren’t expected to counter terrorists, but to counter the ‘terror’ aspect only? It doesn’t matter whether the measures are actually effective against attackers or even cost effective. Sometimes the measures can actually increase the opportunity for terrorist attacks (creating queues outside airports). The primary benefit is to help people believe that the terrorists are being countered, and thus help people relieve themselves of ‘terror’ (and be thankful to their elected government). In this way terrorists are countered and reduced to mildly annoying mass murderers.

So, rose tinted spectacles along with Douglas Adams’ fear sensitive sunglasses (as worn by Zaphod Beeblebrox in HHGTTG) demonstrate the same approach, i.e. fear can be more harmful to a society than the actual harm itself. Doesn’t help those who are actually harmed of course… :-/

However, I think I would feel guilty about using it, imagine the frustration of the person unable to recline!

It did actually happen once - a woman repetedly tried to recline her seat but there wasn’t enough room with me sitting behind it. She thought the seat was broken and swapped with her partner so he could have a go, but failed. I felt bad, but not that bad because I never recline my seat anyway, as I don’t want to inconvenience the person behind me.