I think he meant to AFK for the spawner to spawn mobs. As they don't do that when you're away.There is already a thing called ''Offline progression'' which means you can leave your world and your trees will grow anyways if that is what you meant :)
Being afk to farm mobs is allowed, though they will get kicked because the server will have to refreshI think he meant to AFK for the spawner to spawn mobs. As they don't do that when you're away.
Feature???