There are no ties in Black/White due to recoil. Never have been, never will be. You cannot have a tie on wifi, there are tie breakers in place on the cartridge. You CAN have ties in DPP and back due to recoil, but not in BW.
DU's mon killed kidogo's mon, then died to LO recoil. apparently in-game the game ends as kidogo's mon is killed, so the LO faint doesnt happen and the win is awarded to DU due to tiebreak mechanics. or so ive been told :]