I think banding varies from pitcher to pitcher even on a single plant, since even though they have the same genetics, I don't think that means it'll be the exact same coloring in each pitcher.
Also, if the 'half & half' pigmentation is from Flava hybrids, wouldn't all native Flava var. rugellis be half and half, unless all the original plants in the site were the exact same banding? Even one other type of banding (ie, vertical instead of horizontal) will result in swarms of variable Flava offspring! (ie, the cross-shaped banding) There might've been some 'pure' spots where only,say, horizontals grew, but they've had thousands of years growing and crossing and maybe introduction of the other type of Rugelli by seed dispersal. If that was the case even before the CP enthusiast even was alive, we probably wouldn't even be discussing this subject since all the Flavas would be 'hybridized'! I'm not thinking that a Flava has a horizontal throat band for the same reason that a S. Minor 'Okee Giant' can get huge. An Okee Giant is huge, and when it's crossed into another Okee Giant it's offspring will get huge, while two horizontal banded Flava Rugellis could have vertical offspring! I think the horizontal tends to stay horizontal, but you never know what genes are lurking in the plant itself, or what the offspring will be. I hope to see some input on this subject also, and sometimes it's just real fun to debate about our favorite subjects! That was my 2 cents, or you could say my 2 years of experience with pitcher plants.
Aslan