Facebook Dislike button scam

This one's pretty old but it still comes back every now and again so I feel it's important to put out there.
Facebook has a like button but no Dislike button. Many people including myself think a dislike button would be cool and kinda funny too. Unfortunately Facebook didn't create one because they felt that the dislike button would be abused and used at bad times. Here are some fake examples of when the dislike button would be used causing many upset people.

My Mom just fund out she no longer has cancer - dislike

Just got a new dog - dislike

 We have a new addition to the family today, a new baby BOY!!! - dislike

 Scammers took advantage of the fact many people wanted a dislike button on Facebook. They started creating groups, pages, and even apps that would say "like this" to get access to the dislike button.
All of these are fake, liking their pages won't enable anything except support the scam.

Now even though I just said that these are a scam, there is actually one way you can have your dislike button, legitimately

The only way to have a dislike button without Facebook creating one. Is to use a browser extension, greasemonkey script or add-on.

There is a catch though. only people with the same add-on as you can see your dislikes. This is due to the fact that the dislikes are stored in the addon creators servers and not the facebook servers.
Here is a link to the Mozilla Firefox Dislike button add-on:
https://addons.mozilla.org/en-us/firefox/addon/facebook-dislike/.