A “Do Not Duplicate” key is a key that has the words “Do Not Duplicate” stamped on the top. This means that you cannot duplicate it under any circumstances, as it is the owner's key and not yours. However, a “do not duplicate” key is not legally binding, so it's not a requirement for companies, etc. Having these keys can be beneficial.
The company or person who manages the keys knows how many keys were made in your name and are kept in a register. But, these keys are no more secure than those without it. They offer a higher level of security than unrestricted keys, even those that bear the “do not duplicate” seal, as they are more difficult to copy. So, if you stay out of your house or car and have lost your key, you will know that you have a key with you that you should not duplicate and that can be used as a replacement.
The “do not duplicate” tag on door lock keys is often used to prevent unauthorized people from duplicating keys without authorization. Before buying key locks, locksmiths always recommend consulting the company's key duplication policy. Locksmiths are often asked or asked to stamp the phrase “Do Not Duplicate” on the owner's keys, as they are one of the few companies that can do so. Even if no copy is printed on these keys, they can be copied by any locksmith with the right equipment and skill.
Owners and property managers began to insist on the message of “don't duplicate keys” in an attempt to control security breaches committed by fired employees, former tenants, construction workers, and others who seized a key. So, just like a regular key, in essence, your Do Not Duplicate key is no more special than a regular key. Having a spare key for your home, business, safe, and car can be a good alternative plan in case you lose the original copy of the key. This is because it is assumed that only locksmiths will be able to make copies of these keys and they will have to do everything they can to prevent this from happening and therefore make their home much safer.
In some cases, some unrestricted keys require you to remove the words stamped on the head of the key before duplicating them.