A number of reasons for region coding locking some Blu-rays to one or two regions:
- Distribution rights which vary primarily by continent. It's very common for Hollywood movies to have one studio with distribution rights in North America and a different one with distribution rights elsewhere. A variant of this is the copyright itself which is much less common but has affected some movies being released on Blu-ray (and DVD) in some countries but not others.
- Theatrical release dates vary globally. Some movies not made in the US aren't released theatrically in North America until some months later. This has occurred twice that I'm aware of with recent Terry Gilliam films. Region coding allows disc release in locales where theatrical release occurred months earlier.
- Pricing associated with different demand for a particular movie in North America plus Japan S. Korea & Taiwan (A), Europe including Aus/NZ (B), and Asia (C with the few A exceptions), the three big markets. South America (A), Middle East (B), and Africa (B) markets are too small to influence this.
All these combine to result in region coding on some Blu-rays locking them to one or two regions. I've got some Asian discs that are locked to regions A and B and will not play on a Region C player. You can get region-free players, but Sony doesn't make them. Google for them and you'll find them under all the brand names, including Sony. The biggest factor is the first one - distribution rights and who owns them where.
