Fencer: Two lines can disappear after a move in a corner which completes two perpendicular rows, so I had thought the same applied to parallel rows. The way it is now, sides of the board can become "blocked" and the game's dynamic aspect is reduced. Still, BrainKing is the only site to have this game, so there is no precedent to contradict your method, and maybe I'm just annoyed at losing. :)
Fencer: I think everyone read "between the lines" of the rules and thought that every full line disappears. I think it should be either specified in the rules (as BBW said) or it should be changed to reflect the thoughts of BuilderQ and myself. I'm not saying to go one way or the other (as a disinterested party) but I think leaving the ambiguity will just cause more problems in the future.