On a more personal note, I hate it when I go to copy a link to send via a message, and the tracking code glued onto it is twice as long as original URL... I either have to fiddle around with it to clean it up or leave the person I sent it to to wonder wtf am I on about with a screenful of random characters...
So it's violating users' privacy, it's shit UX, and on top of that, nobody asked for it...