The Sky Steward has an interesting post about BBS, or Big Ball Syndrome:
With so many airlines like Virgin America, United, and JetBlue offering enhanced coach products that provide extra legroom, there is still the problem of BBS (Big Ball Syndrome) which causes many gentlemen to keep their legs spread wide apart. This causes major discomfort to the passengers on both sides of the BBS sufferer. It must be mentioned that symptoms of BBS are often simply imagined by men that wish they actually had BBS.
Hmm, no comment personally since I’m rarely in a middle seat, but I can’t say I’ve noticed this a whole lot. Beyond that, I think the person in the middle seat should have BBS all they want. After all, they’re in the middle, so let them try to make themselves as comfortable as possible.