I'd let him go ahead and mark a spot. Chances are, he'd be marking the wrong spot, given differences in temperature, humidity, age of rails and cloth, etc. If you have skill and are getting used to the table, you know how it plays, rather than placing markers.
If an opponent wanted to do that, I'd say be my guest. Mark every shot, or the whole table. He'd confuse himself to death, and wouldn't account for english applied, and he would be a mess by the middle of the match. You've just described a bad player.