When does a fly become a lure?

[redietz]

It may be more important what the "Game Warden" thinks that what we determine.

Perhaps. Many states have exlicit definitions of what constitutes a "fly" for purposes of fly only water, and while they vary, most that I've seen specifically exclude blades. It's not just the warden's opinion. What an angler chooses to mean by "fly" -- a category of "lure" is his own opinion; what the law says isn't.