How much, if any, trouble he gets in will be subject to the terms of the court order to use the device and the discretion of the judge. You can try to argue that he was not using the car at the time and the camera will bolster that argument.
Worth noting, LifeSaver, one of the companies that produces these devices addresses this subject in their FAQ section: "Can other people operate my vehicle? Yes, but anyone driving the vehicle will need to use the interlock and you will be responsible for any violations." - http://www.lifesafer.com/frequently-asked-questions/#q12
Hope this helps!
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C. Curran Coulter II, J.D.
Attorney and Counselor at Law
THE COULTER LAW FIRM, LLC
8000 Maryland Ave., Suite 1060
St. Louis, Missouri 63105
Office: (314) 721-1116
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Legal disclaimer: The response given is not intended to create, nor does it create an ongoing duty to respond to questions. The response does not form an attorney-client relationship, nor is it intended to be anything other than the educated opinion of the author. It should not be relied upon as legal advice. The response given is based upon the limited facts provided by the person asking the question. To the extent additional or different facts exist, the response might possibly change. Attorney is licensed to practice law only in the State of Missouri and the United States District Court for the Eastern District of Missouri. Responses are based solely on Missouri law unless stated otherwise.
I agree with the prior answer. Your boyfriend can have a probation violation brought against him for the interlock violation, but my be able to vindicate himself with the camera and your testimony. But he also needs to establish he was somewhere else, or he'll get in trouble for allowing another person to operate his vehicle while consuming alcohol.
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