the HDMI device refuses to send an HDCP-protected signal if it cannot synchronize with an HDCP-compatible HD monitor to encrypt the transmission, something called the "HDMI handshake"
Hollywood majors would be scared if perfect copies could be digitally captured from a Blu-Ray disc, but for game makers there is no interest in this
for some reason though every PS3 game signal sent through HDMI is encrypted with HDCP