How would that be unethical? If one could 100% accurately pic out their hets, as some here swear, then how would it be wrong? Nothing unethical about that. In all honesty they will be het or they wont be.
OP. If you want to take the gamble it would be worth it. The female as a possible het sould be no more than the standered normal pastel female price. $400-600 is about standard. Worst case if shes going to be bred by a clown is you will end up with 100% het babies.