Today I looked at the Sandy Drifts record by @Sm4sh and learned that the glitch works as long as you are respawned in the air. I tried this trick out on the eight courses that were Glitchless only and found out that it's possible on three of them.
Pinball Highway - There is a bump you can ride off at the end of the track. You can reach it in only one shoe boost after turning around at the finish line.
Deadly Route - It is possible to ride off the staircase at the end of the track leading up to the graveyard section. I think that it's barely reachable in three shoe boosts if you do them at the right spots.
Turbine Loop - You can ride off one of the two hills halfway through the track. You are in the air for a very short time, and sometimes you don't get any airtime, so this is the hardest one. Three shoe boosts are nowhere near enough to reach the hills, so I drove backwards to get there.
As for the other 5 courses:
Treetops & Highway Zero - Impossible The tracks end in a large fall, so you are completely blocked going backwards.
Shibuya Downtown - Impossible The track is completely flat; no way to get any air.
Dark Arsenal & Studio Amigo - Could be possible It might be possible on these tracks, as they have elevation changes. Unfortunately, the changes are so gradual that I wasn't able to get any air. I didn't try for very long though, so it could happen!
All full game runs have been retimed to use IGT, and the rules have been updated accordingly to clarify this for future submissions to avoid confusion.
No longer will you need to button mash through menus to save a fraction of a second (in fact, please don't do this as it might result in your race
