More adventure, more fun. People who are just as interested in getting adventures out of their ferrets as much as the wild ferrets are must be open to the idea of keeping them untamed. Wild ferrets are quite exciting to behold, especially for extremists who may find themselves bored with the typical domesticated pet. The good thing about wild pets is that they are extremely resilient and able to bounce back from attacks easily with they speedy and adventurous nature. Their curiosity may also lead to bring you in some surprises you wouldnt otherwise have had if you had them tamed.
Non-deviation from their natural genetic makeup. The genetic makeup for ferrets is that they roam free and explore unchartered territories fearlessly. Leaving them to their wild side will enable them to do just that. If you are planning to research on ferrets, keeping them wild is the best way to keep them as close to their natural habitat and actuations as possible. This way, learning about your pet is maximized.
Owners will get the chance to see wild ferrets as they are, sans modifications that can be painful for them. Seeing ferrets au naturel has its perk. Modifying ferrets for domestication such as removing their gland (a big ouch for your mammal!) that secretes the offensive musky smell can really alter your ferret permanently.
One can have to option to train them at a later time. Once you have had enough of the adventures or misadventures of your wild ferret, you always have the option to tame them at a later time.
Wild ferrets may choose to be free from your ownership anytime. Since wild ferrets are designed to be free from any form of captivity or ownership, they will have no sense of loyalty whatsoever and will be free to roam around to places in any way they choose. If you truly want this whole thing to work, you have to be prepared to lose your ferret over anytime once they decide to break free and change their surroundings.
They have higher risk to diseases and early deaths. Wild ferrets are not regulated in any way. They will eat anything and everything that they see lying around. In fact, even domesticated ferrets still have this as a common cause of death. This risk to early deaths, lack of digestion and poisoning may be heightened. And treating them with a laxative may be all the more difficult if you have not trained your ferret even to get familiar with you to trust you.
They may pose a danger to you, especially to children. If you let ferrets be, they will remain as wild as ever and they may not be the kind of pet you would want to have around when there are many children who can get hurt. Children and ferrets are both playful and grow wild when untamed, and there is no predicting what kind of explosion may occur if you put them together in the same room and in the same condition.
Younger children are at a higher risk of getting bitten because they may not be able to regulate the way they touch your ferrets and the ferrets might interpret the childs playful cuddling as an attack.
Once you decide to train them later, they may be most resistant to your attempts. Training wild ferrets when old may not be as easy as when you start them out young. You might have to incur additional expenses and few ferret trainers will be willing to get bitten by an old wild ferret for a fee.