Also Karen just flipped through the folder but didn't stop to read or pay attention to the envelope. She already knew/expected it to be there, and used her thumb to keep the weight of it from shifting and falling out. If they didn't know what was in it already, they probably would have stopped to read it going off of everyone elses reactions. It makes sense that Sr would also leave them a note. What theirs says, I don't know.

Edit: also very interesting that Obama didn't keep eye contact with Laura while they were shaking hands. He looked away completely.