If the Copper 4 day pass is like the WP 4 day pass, there will be a picture involved. With RFID, the pass will be in a pocket, but the rare liftie might ask to see it. Not likely, but it could happen. A couple of months ago I watched a couple of guys get busted at Mammoth finishing out the day on their wives' day tickets. The gender mismatch might have tipped off the liftie. They had some story about alternating child care responsibilities with the wives. Mammoth takes such things very seriously and I have heard that they pay a bounty for such captures. The two were given a choice between ponying up the cash for a full day ticket or a meeting with local law enforcement.
Aspen now sells a parent season pass, that address that very issue. Same price as a regular, it's a good deal.