Tbh it seems like EA/BS has no idea what the difference is between multiboxing and multiclienting.
Multiclienting and multiboxing is the same thing.
Taken from wiki
Multiboxing refers to playing as multiple separate characters concurrently in an
MMORPG. This can either be achieved by using multiple separate machines to run the game or by running multiple separate instances of the game. Multiboxing might be considered a form of
cheating.
[1] Multiboxing is considered to be difficult to do well without practice, as it involves adapting to problems in real-time.
[2]
In this thread we got informed that EA/BS has banned XX player for multiboxing, witch is the same as multiclienting witch is legal, but its the same thing..lol
Furthermore some nice chap posted that multiclienting is legal according to messana. So my bet is that EA/BS definition of multiboxing is someone who uses cheats/scripts and multiclienting, witch actually boils down to someone who cheated/scripted.