Nope brother, Not at all...Both will not be rejected...
CIC will ask to the applicant whose file is more ahead compare to other spouse's file....To withdraw his/her application...
I have closely observed one case from London Visa office in which Husband and wife has applied on two NOC on FSW13. wife's application went faster and London VO has asked permission to them to withdraw one application (husband's)....
CIC sent PER (App number+UCI) to both of them earlier of this permission....
But my suggestion is not to apply for both although each of u are eligible..Be confident with urself...
I hope all confusion will be cleared now...