Activision Support has posted the security and enforcement policy for Call of Duty: Black Ops 3, listing ways you can get banned in-game.
You can get banned for the usual as expected — boosting, glitching, getting unauthorized content, and more.
One thing we’d like to highlight: be sure to keep what you make in the paintjob appropriate.
Any user who creates an emblem or paintjob that is considered to be generally offensive is subject to penalty. Offensive content includes, but is not limited to, sexually gratuitous images, culturally offensive material, and/or foul language.
Any user who creates an emblem or paintjob with personal and/or private information for either themselves or other persons is subject to penalty. Personal/Private information includes, but is not limited to, email addresses, phone numbers, physical addresses, and full names.
You can read the entire thing HERE.