Oh, come on, I got a little chuckle out of "recline-hole".
cordelli's idea is a great one, BTW. ^ A choice for reclining or non-reclining seats sounds like a great way to defuse this long-standing argument.
As for the Knee Defender, that thing has been around for a few years and made enough of a run in the mainstream media that most airlines took notice and specifically banned it. Although I think the tool was an interesting idea, I don't think I'd personally have the stones to use it.