Rationale
The use of ICT is an attempt to prevent individuals from creating unauthorized high-resolution copies of copyrighted content. Without content protection, users with the appropriate equipment could easily capture each and every frame of the film at its full resolution, effectively making a "perfect" copy. Although this danger is greatest for unsecured digital outputs, analog outputs also allow copies to be made, albeit with a potential for slightly reduced quality.
Some HDTV early adopters object to the ICT flag because initial HDTVs did not incorporate HDCP support and thus, if this was activated, these individuals would not be able to enjoy high-definition video from such discs.
Read more about this topic: Image Constraint Token