
Maybe someone overheard a human talking about it? Like a gamer, an arcade technician, or Mr. So who? And how did 'they' know it would allow them to alter the game's code? Where did King Candy get the code? It's written on a napkin from Tapper's, so I think that strongly implies someone 'told him' about it. Then again, perhaps to ensure two consistent rosters between the two cabinets, it may make sense that they are articulated that closely, with one computer powering both cabs (highly unlikely given the resources and processing power necessary to drive two cabs at the time). Most racing arcade games resort to system link via a LAN cable or similar alternative to provide multiplayer. Definitely a case of Artistic License. WRECK IT RALPH SUGAR RUSH SPEEDWAY GAME ONLINE FREE DRIVER
In-game, there are two camera-toting marshmallows who have the duty of supplying the video feed for each player's race, with one getting player 1's driver and the other getting whichever driver player 2 chose.
Both stations are the same Sugar Rush game. that would mean everything was perfectly fine in the other one. But, I'm 'assuming' that they would still be the one game, but that leads to the question of, What if there are multiple copies of the same game in the same arcade? But in the slight possibility that there were indeed 'two' Sugar Rushes. I mean, at the very end, Vanellope is racing on one screen, while the other screen is one that 'Press Start'-type screen. It kind of looks like there are 'two' Sugar Rush's in the arcade, right next to each other? Not the most familiar with arcade games I'd assume they're still connected somehow? I'm not saying it has two screens- there's a tiny bit of space in between, it looks just like two 'different' games next to each other would. so what? What are they going to do about it? Declare the game out of order because one character seems to be missing from it? Theorize that an entire world exists inside of the arcade's power strip and that the girl on the side of the console was part of some conspiracy where she was dethroned and turned into a glitch due to someone sabotaging her code? Even if they did see the picture of Vanellope and did pay special attention to it and did think it was some sort of glitch, as opposed to just attributing it to the "random" roster selection. I frankly don't see why any of this even matters. Or maybe that she's a character who shows up very rarely. Unless there was someone who went to the arcade every single day, they could just assume she's a character that they keep missing. The character roster changes every day. They drop it as Lady Not-Appearing-in-This-Game. Why did no one ever notice that she wasn't a playable character for years? You'd think that at some point someone would point at the picture and ask, "Hey, who's that girl?"
In fact, her picture takes up a huge chunk of it.
Vanellope is on the console of her game. In which case, it's not that double stripes disappear when stood on, they just disappear when collided with in order to mimic breaking away. It could also be used on shortcuts where you 'break' through branches to get to said shortcut. That one branch Calhoun and Felix walked on was huge. It's probably a racing hazard on one of the courses, and trees outside have the same properties.
Maybe it was from a Sugar Rush platformer that came out before Speedway did. Perhaps the track feature in question involves racers attacking opponents at which point the taffy tangles them up or pulls them back onto the track, all the while laughing at the misfortune. Which might actually explain their propensity for Black Comedy. Likewise the Laffy Taffy would probably entangle your car if you used attack-items on your opponents too often. There's probably a Candy Cane Forest track where you drive on undersized branches and vines, so the double-striped ones would be a decent obstacle. Why is there stuff like disappearing tree branches in a racing game?.
Different characters, different motifs and sponsors (a, say, green tea-flavored Pocky-themed racer wouldn't sell as well in America, so they replace that racer with Rancis) and a slightly different art style to fit Western consumption. The Japanese and American versions were probably quite different.
Perhaps the creators of that game wanted to mix Western and Eastern style. Changed in localization? Best I can think of. Why do the Sugar Rush characters have Four-Fingered Hands when the game is implied to be Japanese?. Or they thought they'd be dragged out of their system and executed there.