Question Regarding Multiboxing

I'm sorry if this has been brought up, I can't seem to find a good clear-cut answer. I understand the ToS state Multiboxing causing Harm to players is not allowed, I.e PvP multiboxing / Ganking in world.
I have been told that multiboxing for Bank Alts is fine however.
My question relates to multiboxing PvE. I've heard that you are allowed to multibox so long as both accounts do not engage in PvE combat at the same time. (Having your 60 /follow to scare the opposite faction and deter ganking)
Does this apply to say using your 60 to clear all mobs in an area for slay quests, or killing all mobs and then having your lower character loot the quest items? Are you allowed to power level through dungeons?
Or are you simply not allowed to multibox under any circumstances?
I have been told that multiboxing for Bank Alts is fine however.
My question relates to multiboxing PvE. I've heard that you are allowed to multibox so long as both accounts do not engage in PvE combat at the same time. (Having your 60 /follow to scare the opposite faction and deter ganking)
Does this apply to say using your 60 to clear all mobs in an area for slay quests, or killing all mobs and then having your lower character loot the quest items? Are you allowed to power level through dungeons?
Or are you simply not allowed to multibox under any circumstances?