The "commitment" at this point of time is one way and non-binding. USC got a verbal commitment from a pending 2007 grad back in the spring.
At this point in time, he has stated that he is planning on attending UNC and is no longer actively seeking to be recruited by anyone else. In conversations that occurred on campus, a university may make their intentions know to a younger potential recruit, but nothing can be put on paper until the NLI date of his signing class (next November).
In the Carolinas, this has been very common with USC and occasionally with Clemson over the years. Lately, UNC has begun to actively seek out these under-classmen, probably in response to the agressive recruiting of USC in the area.
In Ben's defense, he wouldn't have made any commitment known unless there were verbal assurances given him on the side of UNC. The colleges in our area have a good track record of living up to their verbal commitments.