Martin actually does get caught quite a bit doing the fend. If he does it when he's standing still, or hasn't developed a full head of steam, or the tackler comes at him from an awkward angle, they do get him. When this happens, Martin has developed a little dinky chip kick, where he drops the ball on his foot with one hand and flicks it in the direction of a teammate. It's usually not very effective - it's just like a rushed, pressured handpass where the player HAS to dispose of it.
The fend-off looks great, but is slightly

overrated. As much as anything, it enables the player with the ball to change direction quickly and maintain balance. Generally, if the tackler falls over, it's as much because HE has had to change direction suddenly to match Martin's movement and is slightly off-balance - then he just needs a little shove to send him to the ground. But you see would-be tacklers fall over when missing a tackle all the time. Plenty of players can dodge tackles without doing a fend.
Still looks great. But every Richmond fan has that uneasy fear that one day an opponent will get a good grab of Martin's arm and drag him down onto his shoulder.