Erin had stood when her companion did, but pulled back during the discussion.  Seemed more polite to let him do whatever he was going to do without her interference.  But when she'd seen Renard steal money from him, she'd glanced to the others, assuring that Abia and any other guests had seen his action as well.  They had, and were a lot better qualified to deal with it physically than she was, so she just moved to block his exit at the table.  She wouldn't be much good in a fight, but she could at least slow him down by making him try to go around her.