From what I heard, it is allowed as long as it doesn't affect money. If someone was like "Pay me 80$ and I will give you full prot IV" then you tp to the guy after paying, then he kills you. Other than that, if some guy is like "TP to me and we will go and kill stuff" then he kills you... it is your own fault.
It is allowed. If the person your trying to trap accepts the tpa or tap's to you.. then thats on them.