Oblivion's colour scheme is not really orange - it is black all the way, with orange
accentuations. From a visual perspective, having bright orange details contrasting with pure black surroundings creates a very striking, slick appearance. It was a genius move in my opinion, thinking outside the box - instead of the usual 'scary' rollercoaster colours.
However, the colour orange by itself does not evoke the right emotions. By painting the pipes bright orange it throws the colour scheme off balance and looks noticeably goofy, for what is supposed to be an imposing ride. What's more they only painted some of the pipes orange, there are still many faded black pipes around Oblivion's tunnel exit and X-Cell. And they are only there because Fanta's colour scheme is bright orange, and Fanta has nothing to do with Oblivion! Even when the ride was sponsored by Coca-Cola, they didn't go around painting the theming red.
CoasterCrazyChris said:
While they are at it, they can scrub the paint off the concrete logos too.
I agree that unnecessary fiddling is very annoying, especially when the ride looked great in the first place. However, I don't see a problem with the painted logos, they hardly make much difference painted or unpainted. In fact, I am surprised the didn't think of painting them in the first place, they look quite effective now because the paint acts as a highlight. All the other logos are orange - why not those around the drop zone?
EDIT
I've just noticed looking at old photos that the chevrons around the Rehydrator were in fact red to match the Coca-Cola colour scheme. However, this is unintrusive because the majority of the building was still black, and the Rehydrator used to be a drinks shop anyway. I guess they changed it to orange to match the rest of Oblivion once the sponsorship ran out.