This NY Times article is a must-read on digital rights management.

Law school hypo – Customer buys, let’s say a Tivo-enabled receiver from a satellite or cable tv provider. Vendor does not reveal to customer that the box contains DRM technology which vendor can enable remotely.  Vendor does so, effectively prevent customer from engaging in legal behavior, such as copying for time-shifting purposes.  Discuss the rights of the parties.  Be sure to analyze under both state fraud laws and federal consumer protection statutes.

p.s. Here’s a starting point if you don’t get the Top Cat reference.