Seacor said about what I was going to say. I suspect that Nintendo didn't create Mario Kart 7 with patches in mind, so it wouldn't be an easy fix. If they wanted to fix it, they'd probably have to do something that's similar in goofiness to Zelda Skyward Sword's Save Data Update Channel. There were several tracks in Mario Kart Wii that had this kind of glitch, and they never got fixed. I had just hoped that Nintendo developed a better checkpoint system in the next game, but it would appear not. Ten bucks says there are more glitches like this one that will be discovered.
I'm sure that future Nintendo games will allow patches, though that may be limited to ones made to accept DLC. Plus Mario Kart 7 was obviously and even admittedly a rushed product, though that was even more of a reason it should have had the ability to be patched.