I have commented already about the dangers of NLP. Here is Wes talking about it now too.
One thing they will do is keep eye contact with you while nodding their head to get you to agree, and then they touch you as they look in to your eyes, that is called anchoring.
Do not under any circumstance allow this to happen to you, even some retailers have their staff doing this to pressure you into buying something that you do not really want. Keep your wits about you and question everything.
At any public event be very careful who you talk to and above all do not let them touch you. if you feel them looking into your eyes, please break contact, walk away.