Thats true, he could pull a "Mike Tyson".  There is no doubt that he is getting payed over 6mil to show up, win or lose.  But he does say he has seen a hole in silvias game and that can beat him.  Which I think he can, I think silvias hole is in takedown defence and another hole in when he is on the ground,  If couture takes him down, and silvia leaves something open or makes 1 mistake Couture has the skill and knowledge of ground game to submit him easy.  
On the other hand, even though Silvia does not look cut or lean, I would say he is training harder than Couture.  He knows couture can submit him is he goes on the ground.  So I would bet money he is working on takedown defence 99% of the time when he is sparring.  I'm sure he is also working on his ground game.  
If Couture fails a few take downs and catches a few right hands from silvia though, hes going to sleep.
It can easially go either way, and be a good fight.  Not a long one, but a good fight.  I cant imagine it going passed the 2nd round.  Either by TKO or submission.