[Shanmancan]

Agreed, trapping only applies when a robot is purposefully attempting to keep an apposite alliances ball away from them by using field elements or other robots on your alliance.

G12
An ALLIANCE may not POSSESS their opponent’s BALLS. The following criteria define POSSESSION :

D. “trapping” (overt isolation or holding one or more BALLS against a FIELD element or ROBOT in an attempt to shield them).