To answer the question, it already is banned. If the fish didn't voluntarily take the bait or lure in its mouth, then it was snagged. Flossing is merely a "high-falutin'" term for a type of snagging.

More interesting, I think, are people's motivations to snag or floss. If a person's intent is to enjoy sport, then he or she ought to employ the concepts of sport. That includes giving game a "sporting chance." That led to what have become the rules of "fair chase." That led to the current regulations which require that a "fair caught" fish is one which voluntarily takes the bait or lure in its mouth. A "foul caught" fish is one that is hooked otherwise.

Not everyone fishes for sport. In the U.K. and the maritime provences of Canada, salmon belong to the owner of the riparian land rights. Commoners and peasants have no legal access to the fish, so there have been long standing traditions of poaching "his lordship's" salmon by gigging them with spear, gaff, or snagging tackle. The "sport" in this case is to get away with taking the lawful property of members of the upper class, who own the land, rivers, and the fish therein. It's part of an extention of what might be termed historic class warfare, in a way.

It's theft by law. However the laws were written by and for the landed gentry. One could reasonably wonder how it is that so many who have occupied the land since time immemorial do not own any of it, or the water, or the fish or game. Hence, we have poaching, and it's seen in a positive light by a great many people who at least consider themselves somewhat disenfranchised.

And here in the U.S. we have had poaching since the first fish and game laws. The key difference is that the fish and game are owned by everyone, not just the landed gentry. Tradition, however, endures, and poaching - getting away with something illegal - is seen in a positive light by admittedly fewer, but a still significant proportion of society.

The upshot is that flossing is snagging, and snagging is illegal. But it is representative of a long established tradition and isn't likely to go away as long as there are fish to poach. We're human, after all.

Sincerely,

Salmo g.