Got this to work once on Cycling Road, and all it did was put up a lousy invisible barrier stopping me from going down on the road ;(
Also, I wonder how the tweaking glitch works with stairs. Maybe, and just maybe, the game might load Arceus as being just a little further down the Spear Pillar then where Palkia/Dialga were, instead of being above in the fourth dimension. Darkrai might be able to be obtained easily if you can remove the barriers on Full Moon Island, thus crossing over to Darkrai's (Darkrai IS on the other side of Full Moon Island, right?).
Remember, messing with maps is what the Elite 4 Surfing glitch in the Japanese was all about. And that's pretty much what this is, except this seems less potent and a lot less risky.