There is nothing 'automatic' about gaining fee simple ownership of someone else's property. Any claim has to be adjudicated by the court based on the history, the 5 basic requirements (actual possession, Open and Notorious, Exclusive use, Hostile use, and Continuous / Uninterrupted use), the statutory time, and color of title. Was the possession in good faith or did the possessor know that the property was not theirs.

We don't deal in hypotheticals so that is all you get. Sounds like a homework assignment.