I've also seen Mk's do something like that with their b up in vBrawl
Meta automatically glides outta Shuttle Loop. Glides can be cancelled by pressin' B or attacked out of with A. If canceled via either method right on top of a surface ya can land on, you'll instantly land without lag and can follow up with literally anythin'. Shield, movement, jumping, attack, whatever. In the case of an attack proper timing lets ya glide attack and follow up with another move with zero ending lag on the glide attack. Glide Attack -> D-Smash or Mach Tornado are two disgustingly broken combinations for Meta t' abuse...
Anyways, it don't got nothin' to do with Platform Canceling.
Figured I'd finally do some offline training... and by trainin', I mean ****in' around in training mode, as all I did was derp about and thus no real trainin'.
I discovered Toon can cancel his Up B and instantly grab the ledge by sliding his way off the stage, so long as he's facin' the stage. +1 edge guarding tool, 'cause clearly he didn't have enough as is. Grandly useful against spacies t' outright beat their Side B when they're recoverin' (IF Toon's spin attack has higher priority, anyways). Also, tippered D-tilt -> Up B for legit KOs.