I have been using 2 guest accounts and playing on the same computer and in the same games for about 3 months. I am also able to log in and play with both of my real VW accounts and likewise play in the same games. The way I have been able to do this is by downloading Chrome and Firefox - I have no idea why - which enabled me to have 2 instances of VW open on the same computer. I experimented with other browsers but when I logged into one account - as guest or real player - the other one was logged out.
There are many players who have realised this and who are using this method to multi-account. After playing this game for quite a while the behaviours of multi-accounters becomes very obvious; one of the most telling signs is when I create games and allow it to fill up with players who I know are cheating, then when their stooge guest account joins the game a moment later and I kick the guest account and half a second later the real user player leaves the game lobby. An IP tracer confirms this.
If this problem is fixed so we can all only have 1 instance of this game playing on one computer, I am confident that this will help to stop a vast amount of cheating in the game. This post is only to show that cheating is very easy in this game and it would be great if all the cheating stopped and I hope this message goes some way to making VW a fair and fun game again.