what happens if violation of driving restriction after interlock system has been removed?

Although I do not practice law in the State of North Carolina, here are my initial impressions.  First, with respect to the interlock system, if it is required as a condition of your friend's probation, then its removal could constitute a violation of probation that could potentially trigger more jail time.  Second, with respect to a new conviction, in most states the penalties for DWI increase based upon the number of convictions.  Therefore, if your friend gets convicted again he/she will most likely be exposed to a greater potential period of incarceration.