Ideas and copyright law

Two threads merge!

Arthur mentioned watching Sister Act. BTR1701 said ideas cannot be
copyrighted.

Sister Act was subject to a copyright infringement lawsuit. From IMDb's
helpfully uncited source,

On June 10, 1993, Donna Douglas and her partner Curt Wilson in
Associated Artists Entertainment, Inc., filed a $200 million
lawsuit against Disney, Whoopi Goldberg, Bette Midler, their
production companies, and Creative Artists Agency, claiming that
this movie was plagiarized from the book "A Nun in the Closet",
owned by the partners. Douglas and Wilson claimed that they had
developed a screenplay for the book in 1985, and submitted it to
Disney, Goldberg, and Midler three times in 1987 and 1988. They
also claimed that the movie contained more than 100 similarities
and plagiarisms from the book and screenplay. In 1994, Douglas
and Wilson declined a $1 million offer to settle the case. The
judge found in favor of Walt Disney Pictures and the other
defendants. Wilson stated at the time, "They would have had to
copy our stuff verbatim for us to prevail."