The story:
1) workers have stack mode and standard mode. as you can guess, workers are on stack mode when they are mining (they can stack on top of eachother and can pass through other units). in standard mode, workers have size and can't pass through other units as normal
2) a long long time ago, someone realized you could get workers to go onto stack without having vision of minerals. so, i could go outside someone's ramp (that's blocked w/ 2 workers), i could spam the vespene gas geyser, and voila my worker would be on stack mode (don't worry about these details) and i could then pass over the 2 workers blocking the ramp and enter the base
3) KeSPA disallows this bug, as it is obviously bullshit to get a worker on stack mode to go WHEREVER it wants w/o having vision
4) Recently, go.go[GsP] (player on OGN SparkyZ) found that if your SCV was holding some money, you could walk up to the ramp, and hit "return cargo" then "stop" then "return cargo" etc etc, forcing the worker to go into stack mode and then out and then stack and then out etc etc which effectively forces the worker up the ramp, similar to #2.
5) Although go.go was NOT penalized at the time, KeSPA immediately made this a disallowed bug after the game
6) forGG was not informed and fucks himself over vs Nal_rA just now
7) ow god damnit i just stubbed my toe. holy fuck that hurts