In my opinion, "captive ads" are in poor taste and the branding strategy behind the program will reflect as much. The strategic pitfall to captive ads is summed up by the poplar aphorism coined by the late Marshall McLuhan: the medium is the message. That medium, designed to capitalize on the attention of people in a vulnerable state, clearly sends the message of being the criminal-defense equivalent to ambulance chasing. It's a medium that poorly reflects the truly valuable service an attorney is sworn to provide for their clients. Those that choose to market their expertise in this manner are committing a branding crime.
This post also appeared on Talent Zoo Media's Beneath the Brand blog.