Considering you drive around in armed cars and can ram people off the track, I'd say that's enough.

Plus, wouldn't anyone put two and two together and realize they never even saw Scotty before? At least Vanellope was explained as a glitch in the game.

Okay, so they would at least know that Scotty signed up fair and square (assuming he signed up the way the rest did), but that does mean he'll have to fight on his own in the race. Much more satisfying to beat the others because You're Just That Good.