Implied consent is a form of agreement that is given through action or inaction, or can be inferred from certain circumstances. This is in contrast to express consent, which is given directly and explicitly in words. An example of this can be seen in the case of Latimer vs. Roaring Toyz, 601 F, 3d 1224 (20).
In this case, Kawasaki hired an independent photographer (Latimer) to take pictures of Kawasaki motorcycles with promotional material related to a bicycle exhibition. These images were later used for promotional purposes in Cycle World magazine and on the Roaring Toyz website. Kawasaki and Roaring Toyz argued that there was an implied license to use the photos in all of these contexts. The court ruled that Roaring Toyz had an implied license to use the photographs for the bicycle exhibition, but not for any other purpose. The license had to be implied because the original contract was between Kawasaki and Latimer, not between Kawasaki and Roaring Toyz.
It is not enough for a person to simply believe that a license exists; there must be facts from which the court can infer that both parties intended to obtain a license, or would have intended to obtain it if they had focused on it. If an author or other creative artist makes it clear, for example on their website, that they do not accept unauthorized use of their material (due to the difficulties involved in constructing implied licenses based on often ambiguous facts), then if you want to reuse someone else's work in your own manuscript, it is best to get permission or check if it is argued that it is a legitimate use. More information on fair use can be found here. While this model instruction accurately captures a recurring set of facts related to implied licenses, implied licenses arise in a wide variety of circumstances, including many where express contracts are not enforced due to fraud law or partnership agreements, and where the elements of an implied license will be different. Implied licenses usually arise when the licensee has purchased a physical embodiment of some intellectual property belonging to the licensor or has paid for its creation, but has not obtained permission to use the intellectual property. Another example of an implied contract under law may be if you are often hired by many of your neighbors to break the law.
In England, there is a greater tendency to consider all implied licenses as issues of fact and intent, while what would be an implied license by law in the United States is treated within the framework of some other branch of substantive law, such as the doctrine of non-derogation of grants.