I think what this guy is saying is try to keep weight over your front foot. I also try to keep my shoulders parallel to the board when flatbasing to make sure its not going to start turning on me.
Thanks...yes. If your board is generally going down the fall line and your weight is on the nose....there is no edge to catch. To demostrate to yourself, put a 10 pound bag of sand in your front binding and it will go right down the fall line and not catch and edge. Next, put the bag in your back binding and the tail will swing around to go first...meaning when your weight in in the back seat. Additionally if your shoulders and hips are not closed/paraelle (or rotated open) this will also add the tendency for the tail to swing around...and when it does you are at much greater risk for catching an edge.
A way to practice not catching an edge at a slow speed is to ride 1 footy or on flat cat tracks.