A grey bearded bikers question.

I have a question,a bit long winded,but only a simple question.When I first started watching motorcycle racing,at Crystal Palace or Brands Hatch and the only Japanese bikes on the tracks were Honda Benlys with race kits,most of the bikes were naked.The riders used to make themselves as small as possible and were one with the bike.Then we saw Mooneyes Cooper riding a faired in bike and hanging a knee out as he went into a bend.I thought this knee out cornering style was to help late cornering because as the knee came out his head and shoulders came up from behind the fairing and acted as a airbrake.
Now I hear that along with the change in tyre shape and knee pads it helps control the angle of lean.
While I was watching the MotoGP Sunday I noticed some of the riders hanging a leg out at the end of the straight and some way before the bend then put the foot back on the peg and leave a knee out as they hit the bend.Now my question is,why.Why hang the leg out waving in the air.Doesn't it upset the balance,I can see how it might stop someone passing on the inside but there must be some other reason.Anyway,it looks ugly.