GNU GPL - Copyright helps Copyleft
Enforcement case timeline

In chronological order
some user sends us a note he found our code somewhere
reverse engineering of firmware images
test purchase to verify device ships gpl-incompliant
sending the infringing organization a warning notice
wait for them to sign a statement to cease and desist
if no statement is signed
contract technical expert to do a study
apply for a preliminary injunction
if statement was signed
try to work out the details 
grace period for boxes in stock possible
try to indicate that a donation would be good PR