Ksurfer and Jake, good points.

Technically, they are moving backwards due to the current, although it may not be apparent to another boat affected by the same current. Same could be said for luffing (being moved backwards by the effect of the wind and waves on the rig and hulls). That may be why the rule is written to only look at backing a sail.

Tony: "IMO if you are touching the sail or using any other way to control the sail other then the proper controls (sheets, etc) I dont think you can call it backwinding."

Have you ever seen anyone stand on their bow, grab the jib, and push it against the wind to back away from a beach? Have you seen a uni-rig (or anyone else) get out of irons by pushing out the boom? You can absolutely backwind a sail without using a sheet.

Mike