From the Oracle rulings:
11/24/2014: A card’s owner is public information at all times. If the two cards you exile are owned by different players (perhaps because you gained control of a Jeskai Infiltrator owned by your opponent), which card is which is no longer hidden from your opponent…
I imagine A would shuffle their top card and N's card, but be obligated to answer honestly and completely any questions about which was owned by whom, which would probably come up if A asked to unsleeve the Infiltator.
Edited Alexandra Yang (July 4, 2015 01:58:04 PM)