The rules state that "launching, shooting, throwing, etc." of a team marker into the depot is not allowed. Launching is defined as "propelling Game Elements into the air." However, it seems that dropping or forcibly pushing a team marker might also be considered propelling it into air.

How far away from the depot does a robot need to be to be considered to be "launching" the team marker?

GDC: This question was previously addressed by several posts in the "Autonomous Period - Answers" thread.