In the CanCan Soccer event, a robot can only have possession of one target can at a time. So what does “possession” mean? Possession in this event is different than “captured”.
For CanCan Soccer, any can that is physically touching the robot is considered to be in that robot’s possession, whether the robot “knows” the can is there or not, or whether the robot has “captured” the can or not.
A robot doesn’t need to possess a target can to score. If a can passes through a goal, a point goes to the robot aiming for that goal.
If a robot inadvertently scoops up a second can on its way to deliver the first, that second can is in the robot’s possession whether or not the robot “knows” it is there, by virtue of its physical contact with the robot. In that case the judge will remove the second can, even if it has been pushed through the goal along with the first, and place it at its original position, and only the first can will count as a score.
If a robot possesses a can and accidentally entangles the opposing robot who has no can in its possession, the reset rules of CanCan Soccer say that the first robot is the only robot that can call a reset. If the first robot is being pushed backwards and looks like scoring is unlikely, calling a reset would be a good idea. However, if the first robot is moving towards the goal and looks like it might score, it would be in its advantage to not call a reset. But what happens if on the way to the goal the second robot touches a can? At the time of contact the second robot also possesses a can, so it could also call for a reset. It would be a lucky robot indeed, since not only does it stop the entanglement, but the reset would stop the likely goal of the first robot.
If a robot using a launching strategy, lines up a group of cans then hits them all at once sending multiple cans through the goal. Only one can would score, since at the point of contact the robot had multiple cans in possession. The judge would place all the cans but the first back to a position of his choice. If the robot when down the line hitting one can at a time, each can would score.
What if a robot has possession of a can and is heading for the goal, then brushes a second can? In this case, the robot briefly has possession of a second can. The judge, at his discretion, could move the second can to a new position, or leave it in the same position. The first can would remain with the robot.
The rules allow the robot to attempt to kick or launch a can into the goal from mid-field, there is no requirement that the can actually be “in the robot’s possession” when it crosses into the goal, in order to count as a score. So, for example, in the unlikely event that a loose can rolling across the floor is accidentally bumped into a goal, that can will count as a score, whether the robot aiming for that goal caused the can to roll into the goal, or it was just luck.