Rockstar has begun to ban users from GTA Online for PC for using some mods.
A sub-reddit has begun to fill up with posts about users getting banned for mods that make cosmetic changes as well as ones that provide an unfair advantage.
In a reply to a user, Rockstar stated that cosmetic mods are not a bannable offense. However, a mod that increases the game's field of view, while cosmetic, does appear to be bannable.
A FOV mod would inject the game's memory the same way a trainer does. This would sound alarms at Rockstar.
Adding to the confusion is Rockstar's reluctance to reveal a list of bannable offenses in GTA Online.