I see the two as being comparable.

If you wife thinks she is not being paid enough, then she should look for another job that pays better.

My opinion is that this is NOT the right time to ask for a raise.  Stick it out.  She should do her job, to the best of her ability.  After this time has passed, that would be an appropriate time to approach her boss/employer, point out that she was a reliable employee and did her job well, and ask for a raise at that time. But now is not the right time.  Asking now puts your wife in a bad light, in my opinion.