No, you could drop a player even without them lagging out by blocking them in hamachi (so your computer can no longer communicate with their computer over the network).
Since OP2 will suddenly stop receiving data from that player, the drop player dialog will come up, the person can then click "Drop Player" and it will signal all of the players in the game that the person has been dropped (and initiates a resync). Since it only takes one person to drop a player (there is no 'majority' system as in some other games, where a certain number of players have to click the drop button before the player actually gets dropped) this is a way to force a player to quit.
It's not to say it couldn't happen in a direct IP game though. Someone could filter their packets before OP2 got them, and block out all traffic from a certain player (that way OP2 thinks the player has d/ced) causing the Drop Player box to come up.
Even then, there are easier ways to force a player to quit. (I'm not going to explain how).
Anyway, this is a pretty sick thing to do. A form of cheating really (and if we catch you, you will get punished).