I like the idea, but honestly wouldn't want it unless it had fan color sliders. Without it, there would be no real reason why the fans keep filling and emptying repeatedly. Go on a server and it's a virtual sell out, yet everyone it wouldn't mean anything. To a new user, or a old hand at LFS. Since there would seem to be no rhyme or reason why they are thing.
If there wear fan colors it would make more sense and mean more. If you are new to LFS sign on, playing a little with a couple of people. Then some big guns in LFS show up, and all of a sudden after the next race restart the fans are filled with these drivers team colors, that would be more impressive. Then more questions would be asked. "How did you get the crowd wearing your colors" etc. More people would want to try and get a big fan base. Meaning more time on track, more races run.
How I see it, picture the 2D fan art that is in the game now. Those are fillers. Once more virtual fans appear for a given driver, the filler fans would start disappearing down to maybe 10% of the over all fan total. This way it doesn't come down to every fan is tied to some driver on the track. Virtual Fans should only start appearing after a restart for Qual/Race/Practice. This way the server won't do micro pause to update fans during a race. So even if a driver leaves the server until the server is rest the fans stick around.
Then the master server adjust the color sliders for the drivers fans. It does the exact same thing now with car color sliders. It doesn't send a new texture just sends the color values to all the people on the server for a given driver.
Now my fictional time is Horizon Motor Sports the colors are Black, Red, Grey, these colors I would choose for my Fan Colors. It wouldn't mean I drive passed the grand stands and see a whole section with my colors. That would be kind of silly. It would have my fans, mixed in with other drivers, and with the filler fans. The more fans I have in one area would mean I have a large fan base. (Wishful thinking lol) But that area wouldn't solely be mine.