First and foremost, Article 6 clearly says "on a first offense"... and after a warning letter is issued, the company has met its requirements and can proceed with discipline.
Second, the issue is called "forced errors", and you must challenge a "forced error" by grieving the accuracy of the equiptment. In order to do so, you must request that a supervisor drive the truck all day long on the normal business day and compare if there are any "violations" during the ride.
If not, then my friend, your buddy is friend.O.S.
When Telematics was first implemented, many drivers just couldnt get out of the habit of not seltbelting. Its a "learned" behavior that is hard to break if you have done this job for years.
If you can prove that the equiptment is faulty and sending "forced errors" back to the company, then all discipline should be removed and no further discipline ( on that vehicle ) can be taken unless the equiptment is replaced and tested again.
While I will give your driver the benefit of the doubt in this conversation, I will say, that most likely, he is not seltbelting as he should and his methods need to change.
If the company is relying on telematics alone, then you have a chance, however, if the driver is physically observed driving without a seatbelt, then most likely he will be terminated on the spot of the occassion.
Hope that helps you.
Peace
TOS