In cycling this is certainly possible. But Merlier doesn't strike me as the type who would do that. And Mathieu is not very good at hiding when he has the legs. So if I had to guess I would say it is true.
But who knows, it could be a big scheme to drive WvA in the nr 1 contender position.
Well, it's not like Mathieu will suddenly have the freedom of Jordi Warlop or Pieter Vanspeybrouck just because he did not appear to be on top today, so I struggle to see what it would accomplish.