This is simultaneously kind of a neat and totally frustrating category. I learned it and performed a decent run within 90 minutes, but it did require some guidance from Nami, who is the WR holder at the time I'm writing this. Not everything that you have to do to finish the run is intuitive just from watching someone do it, and there are some obstacles to actually finishing a run that I will explain.

It is advised to run this category on version 1.1 of the game, rather than 1.0. The former is the more stable of the two. Also, if you mess up or crash, you have to start over from the beginning. Here we go!

Step 1: Start Career as normal. Load up Warehouse.

Step 2: Immediately pause, end the run. Press up to loop the menu around (slightly faster, as pressing up is 3 menu moves, rather than 4 if you choose to move downwards instead) and select Watch Replay->Save a Replay. It doesn't matter what it the replay is called, so I opt to call mine the letter "A".

Step 3: This is required: back out and return to the menu that has Retry, Tape Challenges, etc. on it. If you don't do this, the glitch won't work. Immediately soft reset the game by holding Z and Start for 2 seconds. (I hold Z slightly before I press Start because IIRC pressing Start by itself is akin to pressing A on the menu screen)

Step 4: You're back at the main menu. Move down to Single Session (you can do Career as well, but Single Session is faster due to less menuing). Advance until you get to the course select screen. Move the highlighted stage to Chicago, the first competition. Immediately mash B to back up all the way out to the main menu.

Step 5: Press up to loop the menu around to Extras->Load Replay. Select your replay that you saved in Step 2.

Step 6: Mash A as the replay is loading. If you are successful, the game will grant you control, thinking you're in the first competition while you are actually in Warehouse. Pretty cool.

Step 7: Get 5000 points each in two heats. End the competition and claim your bronze medal. Restart the competition.

Step 8: Get 5000 points each in two heats yet again. Be careful though--this time, on the Competition Standings screen that appears immediately after your 2nd heat finishes, soft reset the game with Z+Start. (If you accidentally advance to the third heat, you have to start everything over, as the game will eventually crash if you try to continue. Don't mess this up.)

Step 9: Repeat step 4 except instead of pressing right to move to Chicago, press left until you're highlighting Burnside, the second competition (pressing left is optimal menuing.) Then repeat step 5, loading your replay again.

Step 10: This bit is a little tricky. You want to mash A very briefly as the replay loads. If you mash for too long, you will advance to the lethal third heat of the competition and the game will eventually crash. You want to be careful NOT to advance to the next heat. End the competition instead and claim your second bronze medal. Then restart the competition once more.

Step 11: This time, since the game thinks you're in Burnside, get 15000 points each in two heats. Same as before, on the Competition Standings screen that appears immediately after your 2nd heat finishes, soft reset the game with Z+Start.

Step 12: Repeat step 9 except press left once to highlight Roswell, the third competition. Then repeat step 5, loading your replay again.

Step 13: (This is Step Unlucky 13 for a reason.) Briefly mash A as the replay starts, exactly as in Step 10. If you are lucky, the game will not freeze, and you can advance to end the competition as well as the run, claiming your third and final bronze medal. If you are unlucky, the game will freeze and you will have to start all over again. To my limited knowledge, whether it freezes or not is completely random, and this is probably the biggest reason why people don't run this category haha. Also it is mostly menuing, so if you're not a fan of the skateboarding bit of this game, this category is for you XD

So that is basically it. Hopefully this guide is accurate and helpful. Good luck with your 0% runs!

~viewtifulday