I've been thinking of this idea that, there could be such a command (like /tptoggle) that when you use it, it either allows random players to tpa to you, or only allows friends to tpa to you. For example, if I have tpa's from many people from whom I don't know, and I do not know the reason why, I can use the /tptoggle command, where then only the friends on my friends list will be able to tpa to me. And if I want anyone to be able to tpa to me, but I have it set to where only my friends can, I would just use /tptoggle again and then it'll allow anyone to tpa to me.