Working on a church install using a Panasonic AG-HMX100 digital video mixer. Customer now wants to be able to use parts of commercial DVD's and Blu-Ray discs during presentations using the mixer.
This seems to be a hot topic recently. The basic issue is that live production systems and the equipment intended for that market are focused on supporting live, original content where HDCP would not be relevant. Theoretically, you should be able to play any non-protected content through the mixer, but since the mixer inputs are not HDCP compliant, not protected content. Realistically, the HDCP standards address when content protection must be enabled but not when it must not be enabled, thus even non-protected content may be blocked if the source device manufacturer elected to enable HDCP beyond when required.
This might be a good application of one of the HD Fury devices as they are intended to convert non-HDCP compliant inputs into HDCP compliant inputs, but you'd have to see how well that works and converting from HDCP compliant HDMI to HD-SDI would still be prohibited as that would be creating a high resolution, unencrypted digital copy of the signal.
Another possible consideration, but you mentioned this involving "presentations". The religious copyright exemption for public performances is related to the religious use and not to the venue being a church, thus the exemption applies only to worship services and not to use not directly related to worship. Content before and after a service, movie nights, social gatherings, etc. are not covered under the religious use exemption regardless of it being a church or not. So if the presentations involved include events other than worship services, copyrights and licensing are relevant and should be addressed.