Yes, a sink tip fly line could be used to floss fish. If it's observed to be a problem, then prohibit fly fishing with sink tip fly lines during the time and places where the snag fests occur. I've only been fly fishing for 40-some years, and if I wanted to floss a fish that way I'm certain I could have done so by now. Yet it's never happened. Either I'm not very good, or I really don't want to catch any fish that way.

Sg