They insisted in writing that I didn't reveal any intellectual property from my current company during the interview and that they would escort me out if I did. That put a serious choke hold on what I could say - it's all intellectual property. So I prepared with great, great care. Then when I arrived after a day of travel and a flight they insisted I sign a paper that if I did reveal intellectual property that they can use it as they see fit and this signature was a condition of holding the interview. They were hoping I would fail at the conditions they setup and take advantage of that. Impossible to perform on the interview without revealing the intellectual property, so I was just swinging and missing on everything important to protect myself legally.