This could seem a silly question, but it appeared in another topic (here) and I’d like to investigate on that.
So, assuming a player joins a ladder but never challenges any other player, could he move up someway?
The real case is: a bot that is allowed to join the ladder but isn’t allowed to challenge humans. Could it move up?
@AdamR already gave an answer: sometimes players above you quit the ladder or get kicked out of it. In addition, new players arrive at the bottom of the ladder, below you. So it’s possible to move up without actually play a game.
I thought at another way that sometimes occurred to me: I was challenged by someone (lower than me, by design) and, during our game, he moved up because he won another game against a higher player.
Because of that, I wasn’t anymore “defending” my place against lower player but actually fighting against higher player. If I’d eventually win, I’d move up thanks to a challenge made by someone else.
Let’s think now at the real case: the bot joins the ladder and then waits for challenges by new players that have joined after it.
If the bot plays slowly (e.g. using all of it’s time or a significant amount of it) it may happen that its opponents overtake it on the ladder. If the bot is strong enough, it shlould be eventually able to move up, beating them.
It’s tortuous, but it could work… and no human is unnecessarily bothered during the process.