HDCP is only one issue. There are also things within HDCP called sessions and hops. Hops are the easy one... Most devices, like BD players, allow for 4-5 hops on a HDCP session, so an originating device (0), the receiver (1), the TV (2) is just two hops. But, add another HDMI switcher, or split things for audio/video and you may have three or four hops. Usually, this is not an issue.
Sessions are FAR more restrictive! The originating device, or with Blu-ray Disc, the movies themselves, dictate how many displays that can view the movie at once. The HDMI splitter is typically HDCP compliant so when you put in the movie, it will see TWO displays, but only allow video to go to the first display, not the second one.
This is movie-to-movie specific, the do NOT publish session information on discs, and you have no way to know in advance.
HDCP is a cluster 'f' to the consumer. HDMI is gorgeous when you keep it as simple as possible, but nothing as simple as a TV/projector setup is that easy anymore.