Bans can happen based on multiple reasons such as inappropriate content, griefing, cheating, inactivity or verbal abuse. Each report is currently being reviewed by a moderator before action is taken. Any action will be based on the Microsoft, and Xbox policies. If you have any questions about what is considered acceptable (and unacceptable) behavior reference these policies.
If an account is banned, then a countdown of the ban duration will be shown on the main menu screen. The length of ban can depend on the type of report, severity of issue and previous history of bans on the account.
Please email any questions about a ban to email@example.com along with your Xbox gamertag or Steam ID.