I sent some feedback regarding the app to the developers, and asked the following question:
"What happens if someone else tries to scan a deck I've claimed? Do I have to unregister my deck as mine before I give it to someone else?"
And I received the following answer:
"As for your question – yes, decks can be scanned multiple times and be registered under multiple users at the same time. (Only the first registration gets the aember shards though!) Our reasoning (as you pointed out) is that players may trade decks or they may want to follow tournament scores of friends/rivals decks."
There are a number of interesting implications here.
- Each deck is tracked by itself, not with regard to any player.
- Don't leave newly opened decks around unscanned, or someone might swipe your precious æmbershards!
I had a third, but I've forgotten what it was. Typical.