hmmmm if the world is flat then if we reach the edge we would fall off.
going one step further at least one of these edges must be conected to water and if so the the water would "fall off" the world thus no more oceans. last time i looked we still had oceans in the world, thus the world must not be flat.
oh and if you say the water has not had enought time to drain check the records the water level has not moved in a very long time if the water was draining then new land would be apprearing where the ocean was at a few years ago.

Penned by my hand on the 22nd of Scarlatan, in the year 245 AF.