Interesting! Well, for me at least, this produces the normal warp animation, and in Single Player it doesn't seem to work at all. Also, this method moves the warp area about half a tile to the left, which could be useful in some cases.

I should perhaps clarify the proposed "ExtendX" and "ExtendY" properties. These define a field relative to the event position ("warp field") within which the player will be transported to the same position relative to the Warp Target (which is necessary for seamless transitions).