Collision design

Say I have a character that picks up items in a level. Would it be a bad idea for each item to check for collision with the player as opposed to the player checking collision with each item they encounter, both from from a speed and a design pov? Does Blender disable logic for objects that are not viewable in the camera?

To complicate this, I am using dupligroups to create instances of the items like in Yo Frankie, so I can’t use messages to communicate to the item that the player has collected it (because they all share the same name.) You can get a pointer to the item via a sensor and set a property in the item as a flag that it has been collected but setting properties of objects from other objects makes me cringe).