A friend of mine just tried to trick me by cloning one of my contacts. It didn't work but I decided to make this script.
When a chat window is opened, it checks the contact's name against all the names listed in your contact list. If two people have the same name, but different emails, it pops up a small message box warning you.
Don't know if anybody will find this useful, but it's here for the taking anyway
There will be updates, which will be posted here, including things like the option to send a message to the person that has been cloned, warning them.
Restrictions - If somebody has cloned a contact and you start a chat with that contact, it will still pop up the message box warning you about clones. However, this can still be useful information...