Apart from issues relating to adolescence, I think the idea is generally a good first step to be able to costumize in game content, that does not affect other players.
I know HTC's gripe with custom player costumization, but most of it if not all has to do with content that is visible on the plane itself, to other players. That's why skins have to be approved, and then added to the game. This prevents historically incorrect skins, for example. Or me creating a skin that has Megan Fox pictures all over it. Makes sense.
However who cares what I can see inside my own cockpit, apart from me? I think it would add a nice personal touch to every bird we fly. I would have different images in my Spitfire, than I have in my German rides of choice.