BF3 ESP only and BF3 SimpleAim are down - there is a ban wave going on right now for us. Please be patient. Black Ops 2 Info
Treyarch has two types of banning:
Type 1 - Detects Hacks - either by screenshot, or other means - you can be banned on a new key even before you play 1 match.
Type 2 - User Reporting. Other players will report you after suspicious play.
If your tracing enemy movement behind a wall, they will see this while reviewing your demo's (recorded gameplay). They can view all players, and movement from any angle. They will catch you using aimbot, or wall tracing, or pre-firing when no radar is visible.
Our Hack is not detected by Type 1 (above), however you can be banned by Type 2 - with suspicious game play.