It is unlikely that Tony Robbins is using traditional NLP when dealing with a large group. He may use elements of NLP, but traditional NLP is designed to work on a single person.
NLP requires the practitioner to develop rapport with the subject, which is dependent on "pacing". "Pacing" is achieved by mirroring a subjects non-verbal cues (breathing rate, eye movement, posture etc...) and using verbal cues to direct attention to true, easily validated shared experiences (sounds, smells etc..).
Once rapport is established the practitioner will start to lead the subject, using verbal techniques to gather relevant information from the subject's unconscious and break and create associations to modify how the subject sees and reacts to specific stimuli. Throughout this entire process, rapport must be maintained or re-established to continue leading.
Although I've seen very little of Tony Robbins, I suspect he uses a variety of techniques and modalities that are very effective on certain personality types in specific states of consciousness. There may be aspects of NLP used in data gathering or leading, but the way NLP uses pacing and feedback is certainly not part of it.
It is often very difficult to retrain the unconscious, and there are techniques that can be used that require the help of another. We must continue to change and evolve, just make sure you trust both the intentions and the intuition of anyone that you allow to help reprogram you unconscious.
