If you wanna be safe about the transfer you should trade them or something that is not "Digital" in Tibia like Bank Transfer, Parcel and so on. Tibia can see if you have transfered from the Tibia Bank and if they really see alot of cash being transfered then and then you will be banned on both. Not sure about parcel but doing like Standing by depot and giving the cash to the another without anyone watching is the safest way.