Im pretty sure you understand the rule, if a player is doing one click every 200 seconds during most of the game its breaking this rule, if you ask your friend ''hey play only the first minutes of the game them dont leave go to do other think and I ll use you hero give control to all the players for the start'' this also break the rule.
Isnt really so hard to get it, if volkov exist or not is irrelevant.
without using his phantom player maybe dont kill Shadow Arthas
magical rope and 3 runs instead 2 with knot of murgul, bad example)
My point was that Murgul wasnt making a big difference, this just make my point.
they could be done exactly the same without using his phantom player
maybe dont kill Shadow Arthas but still they will easily reach the goal
of the Quest