Nope, they won't. Rules do not allow two bookings on the same flight. They may cancel both on you if detected.

Excerpt from AC Conditions of Carriage:

PROHIBITED PRACTICES - 73
_ G) PROHIBITED PRACTICES
AC SPECIFICALLY PROHIBITS THE PRACTICES COMMONLY KNOWN
AS:
BACK TO BACK TICKETING-THE COMBINATION OF TWO OR MORE
ROUND-TRIP EXCURSION FARES END TO END FOR THE PURPOSE OF
CIRCUMVENTING MIMIMUM STAY REQUIREMENTS; "DUPLICATE
BOOKINGS" - CARRIER DOES NOT PERMIT A PASSENGER TO HOLD
MORE THAN ONE CONFIRMED RESERVATION/TICKET ON THE SAME
DEPARTURE FLIGHT/ORIGIN AND DESTINATION FOR THE SAME
TRAVEL DATE.