First off, I just want to say that I appreciate the small QOL changes implemented in the past few updates. Though the double click to teleport is one of my favorites, I've noticed a bit of an issue.
The double click requirement does not have to be on the player name to trigger. I dual box whenever I play so I teleport to myself.... a lot. And my second accounts wizard is at the top of my friends list, so I can move very quickly from clicking the friends list icon to my alt wizard. It will register both clicks as being fast enough to classify as a double click, and teleports after clicking only once on my alt. You could even already have your list open, click just outside the list, and then on the player. It will teleport you to that player.
This has caused me to teleport to friends multiple times, when I am just trying to send them a text chat instead. Regardless of this bug, my suggestion would be to change it to a right click. I just believe it would feel more smooth for the user.