An unarmed fencer wouldn’t have any special advantage over someone who does other activities, in my opinion. Put them up against a physical twin who did football or rugby, and there’s no question who would win the fight. Give the fencer a stick, and there might be a slight advantage to the fencer. But even there, he wouldn’t have much of an idea of what to do other than poking the other guy in the chest a couple of times before he gets rushed and bodyslammed.
I dabbled in fencing at college, having done some old-style Japanese martial arts for about 3 or 4 years at that point. We did weapons work at my dojo, so I had both armed and unarmed skills.
Modern sport fencing is very, very different from any kind of practical combat. There are complicated rules about right-of-way and precedence that may—at one time—have been meant to substitute for the lack of danger involved in fencing with very flexible edgeless blades, but are now next to useless.
To give you an idea of how far removed from reality fencing has become, Ota one of the world’s top-ranked fencers, favors a whipping over-the-shoulder technique that wins surprise touches. With a real blade, it wouldn’t work at all because the blade wouldn’t bend that much, and even if it did, the hit would be useless for combat because you’d inflict at most a light cut while your opponent has a chance to skewer you.
In modern fencing, getting the touch before your opponent is the only thing that matters. He can “run you through” while you tap him on the shoulder as long as you hit a valid target area with enough force to depress the button on the electric foil a fraction of a second before he gets you.
I had huge problems fencing because I was trained in stuff that worked for real fights, including grappling and disabling or killing techniques. I’d instinctively want to go off-line, bind a poorly balanced opponent and throw him, force a poor guard, cut exposed areas; all things that are absolutely not allowed in foil fencing. The instructor said he didn’t teach epee at all until you were an advanced foil fencer, though epee would probably have been a better fit for me. It didn’t take me long to decide that I didn’t like fencing anywhere near enough to commit to overriding reflexes devoted to real fighting.
I had the same kind of problems with kendo, so Western fencing isn’t alone in being far removed from its roots. Sport fighting is not combat fighting.