Confront them, remind them of what they did, and ask them why they did it.
Or pretend like you don't notice the difference until they either realize how selfish they're being, or wonder why you haven't figured it out, bring it up to you in person, and when they do, ask them why they did it in the first place?
Why replace when you can add to the collection?
WWYD if someone shouted "I lost the Game!!" at a con and someone else had a giant "I saved the Game!" memory card?