Activision issued a cease and desist order against the group and their FOV tool.
It's made even worse when you look back to 2012 when a developer at Infinity Ward said they do not mind FOV changing mods and that they will not ban for their use. Whoops!
We do not mind if a PC user has the FOV changer mod.
We also do not ban anyone that is using the FOV mod.
EDIT: Just had confirmation that Valve also does not issue bans for FOV changer.
Infinity Ward does not realize that FOV sliders are a must in games and that some people even get sick from narrow FOVs without being able to change them. So this huge oversight on IW results in Activision taking legal action against a mod team that was able to do what a major developer could not.
The Activision legal department should probably look into some means of removing their heads from their asses.