I usually carry around a small Swiss army kit my set of keys which contains a small knife inside the slot which is about 1 inch in height and very thin (see link for better picture, and it is described as a blade, not a knife in the picture)
One day when I was going through TSA airport security, I forgot to take off the kit and leave it at home. To my surprise I was able to get through without a problem, or anyone asking me questions. When looking at the TSA prohibited items (link below for reference) it looks like I am not able to bring it onto the plane.
Question: Was the Swiss kit with the knife overlooked by the TSA? If not, is it an allowed carry on item?