I've always thought that by its very definition, seam movement was the random deviation of the ball when it lands on its seam.
I used to attend this cricket coaching camp organised by Kiran More in Vadodara and one of the coaches there used to tell the bowlers to try and seam the ball back into the bowler by angling the seam or something. But I always thought angling the seam is used to produce swing, not seam movement, and so always thought that coach was talking out of his backside. On the other hand I've seen Kulasekara almost without fail seam the ball back into the right hander when he bowls the inswinger instead of it straightening the other way. So is it completely random or can the bowler do something to influence which way it'll move off the deck?