When Xu Zheng and Wang Baoqiang were first paired in 2010's Lost on Way, it was uncomfortably reminiscent of Planes, Train and Automobiles, a 1987 Hollywood comedy unknown to most in China. Later, its makers acknowledged the source. Fortunately, all the jokes and gags were local, specially designed for a Chinese audience.

I often thought this film could get into legal trouble had the Hollywood side learned of it or had the remake ended up being a financial success.

I've heard accusations that Lost in Thailand, the supposed sequel to Lost on Way, borrowed liberally from Hollywood's The Hangover Part II. But the view was not widely supported in China. The only similarity, it seems, is both comedies are set in Thailand and involve buddies.

In China, the legal trouble for Lost in Thailand was the producers' decision to market it as a sequel whereas Lost on Way was made by a different company.

Giving it sequel status would be like hiring Daniel Craig in a separate spy thriller and calling it a 007 movie despite the fact that the character's name is not James Bond.

The biggest such recent controversy is last fall's sleeper hit Goodbye Mr. Loser. After it made 1.4 billion yuan at the box office, a film critic said it had plagiarized from Peggy Sue Got Married, an obscure Coppola film. The filmmakers claimed they had never seen the 1986 American film and decided to sue the critic for defamation.

While the case is still pending, I tend to believe the filmmakers. The two stories share a premise of transporting the protagonists back to an earlier period, but isn't Back to the Future a much better known precedent?

Oh, there is similarity in detail: A character wrote a song that ended up as a seminal work for a big star. But a good comedy needs a hundred details like that. I would call it a coincidence if it contains just one or a few.

When I finish a script, I often change my perspective to that of a critic and will find a dozen or more sources of inspiration for the work. I will mention them in a published article so smart people won't think I'm stealing.

Acknowledging one's sources is a sign of honesty and also an effort to differentiate faithful adaptation and free association and the hundred shades in between.