Exploitation of Open Source VoIP

n8twj writes " With John 'Maddog' Hall pointing out that Open Source VoIP will be bigger than Linux ever has been. How can we be sure that un-ethical companies will not try to steal code that is covered under the GPL and try to pass it off as their own? Recently, I have become aware that SysMaster has been redistrbuting a version of the Asterisk PBX written by Mark Spencer from Digium and many others. SysMaster claims that they wrote everything in-house, while they have surely done their own development, they are using Asterisk to power their product line without following the rules. In terms of full disclosure, my company also provides Asterisk-based solutions, however we have fully embraced Asterisk and gladly contribute back to the GPL."