Ghost friend request and infinite queue times (Client bug)

A few of my friends and I have recently experienced a random friend request from accounts we don't know. Once we accepted these people, they instantly vanished from both our online and offline lists. I noticed that a couple of my friends were in queue for over 2 hours at one point and asked them what was going on and they told me that they weren't even online. I figure this is some sort of attack on riot servers to create traffic and hold up queue times as these accounts never seem to press accept to get in games. However, this does not prevent these players from logging onto the game so they are not losing any control of their accounts. Has anyone else noticed anything like this?