Can you put a diamond and cubic zirconia together in the same setting?

Reputable stores and jewelers usually set CZ in no higher than 10k gold, and they are stamped as such. The CZ is on the inside of the band by the gold stamp.

However, anybody can buy loose stones and settings separately and have them set. So, if a person wants to buy a 14k gold setting and set a medium Cubic Zirconium for the center stone, and small surrounding diamonds, they are still saving a lot of money and the 14k stamp and surrounding diamonds make it look more authentic. There is no law that says a layman can't do this. "Name" jewelers have reputations to protect so I doubt they would 'mix them' like that.