Factual error: In one scene, Mrs. Doubtfire pulls the symbol off of Stu's car. She shouldn't have been able to do that, since a cable connects the symbol to the inside of the car.
Factual error: The piano was invented by Bartolomeo Cristofori in the year 1720, in the 18th century. Miranda recommends a "17th-century grand piano" for Stuart's bed-and-breakfast inn.