Modern smartphones popularly adopt a small touch sensor for fingerprint identification of a user, but it captures only a partial limited portion of a fingerprint. Recently we have studied a gap between actual risk and user perception of latent fingerprints remaining on a smartphone, and developed a fake fingerprint a.ack that exploits the latent fingerprints as actual risk. We successfully reconstructed a fake fingerprint image in good quality for small touch sensors. In this paper, we subsequently conduct post hoc experimental studies on the facts that we have missed or have since learned. First of all, we examine that the presented a.ack is not conceptual but realistic. We employ the reconstructed image and make its fake fingerprint, using a conductive printing or a silicon-like glue, to pass directly the touch sensor of real smartphones. Our target smartphones are Samsung Galaxy S6, S7 and iPhone 5s, 6, 7. Indeed we have succeeded in passing Galaxy S6, S7, and now work on the remaining smartphones. We also conduct an experimental study for one of our mitigation methods to see how it can reduce actual risk. Finally, we perform a user survey study to understand user perception on the fake fingerprint a.acks and the mitigation methods.